Close Program/Task Manager
This is NOT a list of tasks/processes taken from Task Manager or the Close Program window (CTRL+ALT+DEL) but a list of startup applications, although you will find some of them listed via this method. Pressing CTRL+ALT+DEL identifies programs that are currently running - not necessarily at startup. For a list of tasks/processes you should try WinTasks 5 Standard/Professional from LIUtilities or the list at AnswersThatWork. Therefore, before ending a task/process via CTRL+ALT+DEL just because it has an "X" recommendation, please check whether it's in MSCONFIG or the registry first. An example would be "svchost.exe" - which doesn't appear in either under normal conditions but does via CTRL+ALT+DEL. If in doubt, don't do anything.

Operating System Differences
A number of entries are repeated due to the way that different operating systems display startup items. For example, WinMe lists "POPROXY.EXE" as "Norton eMail Protect" in both MSCONFIG and the registry whereas WinXP lists it as "Poproxy" in MSCONFIG and "Noeton eMail Protect" in the registry.

To avoid the list becoming too large, all VIRUSES are shown using the registry version which is common to all Windows versions.

Alternatively use your browsers search facility - Ctrl+F for IE users.

Key:

"Y" - Normally leave to run at start-up
"N" - Not required - typically infrequently used tasks that can be started manually if necessary
"U" - User's choice - depends whether a user deems it necessary
"X" - Definitely not required - typically viruses, spyware, adware and "resource hogs"
"?" - Unknown

Use your browsers search facility - Ctrl+F for IE users.

?	P17Helper	Rundll32 P17.dll, P17Helper	ASIO driver for the Sound Blaster Audigy & Audigy 2 series sound card - is it required in startup?
N	P2P NETWORKING	P2P Networking.exe	Peer to Peer (P2P) sharing of files on the internet
N	P2P Networking	P2P	Peer to Peer (P2P) sharing of files on the internet
N	P2P Networking3	P2P Networking3.exe	P2P Networking, a component bundled with Kazaa that enables other applications to use Peer-to-Peer functionality. Not required - see here
X	P3p4chk	P3p4chk.exe	Added by the GEMA TROJAN!
X	p4mx4	p4mx4.exe	Added by the CRYPTER.A TROJAN!
?	Packard Bell EverSafe Tray Control	TrayControl.exe	Packard Bell EverSafe software. What does it do, and is it required?
N	PadTouch	PadExe.exe	Toshiba Touch and Launch - offers easy movement and freedom of programs navigation with TouchPad
U	Pagekeeper Jobs	pkjobs.exe	PageKeeper Jobs is a separate PageKeeper program that handles the analysis of new documents and keeps track of the location and content of current documents in PageKeeper. Pagekeeper comes bundled with scanners such has HP, Microtek, etc
U	Pagekeeper Lite	pkjobs.exe	PageKeeper Jobs is a separate PageKeeper program that handles the analysis of new documents and keeps track of the location and content of current documents in PageKeeper. Pagekeeper comes bundled with scanners such has HP, Microtek, etc
X	PAgent	PAgent.exe	Scans your hard drive for the popular P2P file-sharing applications BearShare, Grokster, Kazaa, Limewire and Morpheus. After searching the entire local filesystem for any files with those names it connects to the DownloadWare servers and tells it what, if anything, is found. See here for more info
N	Pagis Scheduler	Monitor.exe	Scheduler for the Pagis scanning suite from Scansoft.
?	pagmstart	client.exe	Possibly related to this?
N	Pagoo	PAGOO.EXE	Pagoo - internet call waiting. Intercepts telephone calls like an answering machine and plays the voice message on your PC. Only required when you're on-line and via dial-up modem
?	Palm MultiUser Config	Configtool.exe	MultiUser configuration for a Palm PDA device?. Is it required?
N	Palm.exe	Palm.exe	Palm Desktop Software for use with Palm handheld devices. Available via Start -> Programs
X	PalNetaware	pnetaware.exe	PalTalk adware - as included in Morpheus, see here towards the bottom of the page
N	PaltalkNetaware.exe	PALNETAW~1.EXE	Voice chat program. This program stores all buddy list info apparently on the server itself so you never lose your buddy list should you need to reinstall the program due for whatever reason or even reformat. Available via Start -> Programs. Delete the shortcut in Start -> Programs -> StartUp as well otherwise it will be reinstated
U	Panda Antispam Server Service	PasSrv.exe	AntiSpam software, part of Panda Platinum Internet Security
U	Panda Scheduler	pavsched.exe	Panda Antivirus scan scheduler. Required if this is your virus scanner program and you have scans scheduled on a regular basis. I recommend that you scan manually so you don't need this but if you tend to forget then leave it
X	PandaAVEngine	PandaAVEngine.exe	Added by the NETSKY.R WORM!
N	Paperport	runppdrv.exe	Loads the drivers associated with monitoring scanner status associated with PaperPort software. Can be a resource hog - see here
N	PaperPort PTD	pptd40nt.exe	"PaperPort" software associated with scanners
N	PaperQuote System Tray Icon	PQTRAY.EXE	PaperQuote is a "wallpaper" changer with daily quotes that are either for inspiration or motivation
X	Parallel Tasking	ptask.exe	Added by unidentified adware - recognized by Kaspersky antivirus as Trojan-Downloader.Win32.Small.adg
U	PartSeal	PartSeal.exe	System backup for Sony Vaio PCs. Adds a recovery mechanism for users over and above any System Restore features - allowing users to revert a drive back to the state it was when bought form the factory by hitting F10. The user obviously loses any data stored if not backed-up elsewhere
U	Password Door Loader	PDMonitor.exe	Password Door - password protection software
N	PasteLister	plister.exe	PasteLister - clipboard extender. Start manually when required
X	Patch	patch.exe	Added by the NETBUS WORM!
X	Patches Value	WinGamed.exe	Added by the SDBOT.BR WORM!
?	Path	lide.exe	??
X	PAV.EXE	%Number%	Added by the KITRO.D (or ARGEN.A) WORM! %Number% can be any number
Y	PAV.EXE	PAV.EXE	PER Antivirus
Y	PAVFIRES	PavFires.exe	Panda Antivirus
Y	PAVFNSVR	PavFnSvr.exe	Panda Titanium Antivirus
Y	PavProc	PavPrS9x.exe	Panda Titanium Antivirus
Y	PavProt	PavProt.exe	Panda Titanium Antivirus
U	PC Alert III	alert.exe	MSI PC Alert III - allows you to view your system and cpu temperature, fan rpm and more. Only required if you overclock
U	PC Booster	pcbooster.exe	PC Booster from inKline Global - "easy-to-use computer system optimizer that gives your system the extra speed and stability you want while ensuring that your computer is kept clean and in tip-top condition"
X	PC-Config32	corona.exe	Added by the CORONEX.A WORM!
Y	PCBG	PCBODYGUARD.EXE	PC Bodyguard from Calluna - protects system files and settings from being deleted, modified, etc
Y	PCBODYGUARD	PCBODYGUARD.EXE	PC Bodyguard from Calluna - protects system files and settings from being deleted, modified, etc
Y	PCCClient.exe	PCCClient.exe	PC-Cillin 2002 antivirus software
Y	pccguide.exe	pccguide.exe	PC-Cillin 2002 antivirus software
Y	PCCIOMON.EXE	PCCIOMON.EXE	PC-Cillin 2000 antivirus software. This is the actual virus-scanner
Y	PCClient.exe	PCClient.exe	Trend Micro PC-Cillin Internet Security
Y	PccPfw	PccPfw.exe	PC Cillin 2003 personal firewall
Y	PcCtlCom	Pcctlcom.exe	Trend Micro PC-cillin Internet Security
N	PCDRealtime	realtime.exe	Apparently the monitoring device for PC Doctor Online. It provides a "free" examination on system files (i.e. registry), reports the number of errors it finds, and invites you to "order" the fee-based fixes from its web site
X	PcEXPLODE	specialfile.exe	Added by the RBOT.RH WORM!
N	PCHbutton	PCHbutton.exe	Used by HP Instant Support
N	PCHealth	pchschd.exe	This is a "scheduler" and does not turn off PC Health. For more information refer here
X	PCHEasySearch	STUpdate.exe	PCH EasySearch bar
?	PCIMODEM	pcimodem.exe	Associated with Lucent based Aztech MDP7800-U PCI modems. Is it required?
U	PCLEPCI	ppe.exe	Pinnacle Systems PCI Performance Enhancer. "This tool helps to increase the PCI Busmaster performance of all Pinnacle PCI boards."
?	PCMService	PCMService.exe	In a DellMedia Experience sub-directory
U	PCRecSA	PCRecSA.exe	Part of the IBM/XPoint Rapid Restore backup utility. If you choose, you can use it to create a "clean" backup of your hard drive. The process involves the software partitioning your hard drive, making a compressed image of the working drive which will then allow you to revert to that should you need to
X	PCShield	regsvr32 /s [path] sfg_****.dll [* = random char]	SafeguardProtect/Veevo malware
N	PCStart	Pcm25.exe	Runs as part of PCMonitor which is a program for monitoring your activity on your system. It makes screen dumps and key logging. It can hang-up your system because the screen dump page gets VERY big
N	PCSuiteTrayApplication	TrayApplication.exe	System Tray icon for Nokia PC Suite. PC Suite lets you synchronize, edit, and back up many of your phone's files on a compatible PC through a wireless or cable connection. PC Suite can also be launched through Start Menu
N	Pcsv	pcsvc.exe	Delfin Media Viewer or "Promulgate" adware
N	PcSync	PcSync.exe	If a Nokia phone has been connected, synchronises the phone with MS Outlook or other organiser software. It is installed by the Nokia PC Suite, and the tray icon shows if a phone has been connected. Available via a desktop shortcut or Start -> Programs
U	pctspk	pctspk.exe	Used for modems based upon PC-TEL chipsets. Normally used for some Voice and Speakerphone functions and also for some Power management options. If you remove it you may not be able to use any of those functions
U	PCTVOICE	pctvoice.exe	The program PCTVoice is used by the modem to interface with your computer and also used for some V.80 functions for Video Conferencing. if you uncheck it, it comes back. It’s better to leave it
U	PDEngine	PDEngine.exe	PerfectDisk from Raxco - disk defragmenter. Only required if you schedule disk defragmenting at re-boot
N	pdexplo	PDEXPLO.EXE	PowerDesk Pro by Ontrack. Enhanced desktop and file manager. Available via Start -> Programs
?	PDF Converter Registry Controller	RegistryController.exe	ScanSoft PDF_Converter related - what does it do and is it required?
N	pdfFactory Pro Dispatcher v1	fppdis1.exe	"With pdfFactory you can create PDF documents from any program printing to the virtual PDF printer". Available via a desktop shortcut or Start -> Programs
N	pdfSaver3	pdfSaver3.exe	PDF-XChange - create Adobe compatible PDF files from virtually any Windows software such as MS Word, Excel, AutoCAD, MS Publisher etc
N	PDirect	PDirect.exe	IBM Presentation Director software
U	pdp Server	ctpdpsrvr.exe	Included and setup with the drivers for my Compaq A3000 all-in-one printer/scanner - maybe for networking. Works fine without it - but may be needed when used over a network
U	PDVDServ	PDVDServ.exe	Remote Control background application for CyberLink's PowerDVD version 5 and above. Enables you to use a remote control with your DVD drive if your drive came with one. Not required if you don't have a remote control, or don't wish to use one
N	Pe2ckfnt SE	chkfont.exe	Used to check whether the fonts are installed properly on your computer or not for a scanner. If you don't want to execute it, you can uncheck it in the startup menu
?	Peeramid	PService.exe	In a "Koptimizer" folder in Program Files. What does it do and is it required?
N	PeerGuardian	PeerGuardian_1.99b_pr14.exe	PeerGuardian "is a tiny firewall program especially designed for P2P software users, but also for anyone who is concerned about the investigations that corporations and authorities perform on the internet. PeerGurdian blocks connections for the configured IP ranges and logs the blocked connections"
U	Pent@VALUE 3.2	Pent@VALUE.exe	Pent@VALUE Digital Satellite Internet PC Receiver
X	PeqBL100	PEQBL100.exe	Added by the ENVID.D WORM!
Y	PER Email Protection	pavmail.exe	PER Antivirus
N	PerfectPrint	pfppop70.exe	Print engine used by Corel WordPerfect 7 and Presentations 7
Y	PersFw	PersFw.exe	Kerio or Tiny Personal Firewall
X	Personal Firwall	ptmedsrv.exe	Added by the SDBOT.XY WORM!
U	Pervasive.SQL Workgroup Engine	W3dbsmgr.exe	Database Service Manager for Pervasive SQL 2000 Workgroup edition. Required if you use Pervasive SQL but it's recommended you start it manually before using it as it has a tendancy to crash/freeze if loaded with other applications at startup
U	PestPatrol Control Center	PPControl.exe	PestPatrol Control Terminal - launches PestPatrol features such as PPMemCheck and CookiePatrol
?	PestPatrolCL	PestPatrolCL.exe	Associated with PestPatrol anti-malware software. What does this part do and is it required?
U	Petit Larousse 2001	HIPL2000Popup.exe	Popup dictionary tool
?	PFW_CfgEngine	PFWCFG~1.EXE	Personal Firewall related?
?	PFW_PullSrv	PULL.EXE	Personal Firewall related?
X	PgMonitr	PgMonitr.exe	Delfin Promulgate adware variant
Y	PGPSDKSVC	pgpsdkserv.exe	PGPsdkServ.exe is the new SDK service which is responsible for performing all PGP key management and cryptographic functions. This functionality was moved into a service to allow multiple modules simultaneous read/write access to the keyrings, among other things. As you can imagine, it is necessary for PGPsdkServ to be running in order to perform practically any PGP functionality
U	PGPSERVICE	pgpservice.exe	PGPservice.exe has two main purposes: (1) it handles a large part of the PGPnet functionality (along with the PGPnet driver) and (2) it allows efficient access to the PGP preferences database. The individual PGP modules normally access the preferences through PGPservice, but they are capable of a "fall-back" mode where they can handle such access on their own. Thus, if you are not running PGPnet, you may not immediately notice much of a difference if you disable PGPservice. If you are running PGPnet, you will notice a big difference
N	PGPtray	pgptray.exe	PGP 7.x. Provides icon tray shortcuts to PGP programs from Network Associates. Available via Start -> Programs
X	PGStub.exe	[various filenames]	Unidentified adware
X	pgtaff	pgtaff.exe	AdRotator adware variant
N	Phime2002a	TINTSETP.EXE	Part of Microsoft's Input Message Editor (IME) for translating Japanese/Chinese text in IE, Outlook and Word
N	PHIME2002ASync	TINTSETP.EXE	Part of Microsoft's Input Message Editor (IME) for translating Japanese/Chinese text in IE, Outlook and Word
U	PhoneFree version 6.2	PHONEF??.EXE	An Internet telephony application. Complicated registration and ad banners tailored to your profile - see here
N	Photo Express Calendar Checker SE	CALCHECK.EXE	If you create multiple Weekly/Monthly/Yearly calendars to use as your wallpaper, Photo Express will replace the wallpaper automatically. Photo Express 2.0 has a calendar checker which checks the date on your system and updates your wallpaper accordingly
N	Photo Loader supervisory	Plauto.exe	Casio's Photo Loader software. Hook up your camera to the USB port, and it pops up and asks you if you want to load your pictures
N	PhotoWise QuickLink	quicklnk.exe	Agfa PhotoWise - "PhotoWise QuickLinkTM lets you drag and drop photos right from the camera into your document (applications must be OLE-compliant). Use PhotoWise to print contact sheets and photographic prints. Create slide shows, screen savers, wallpaper and more."
N	Picasa Media Detector	PicasaMediaDetector.exe	Media detector for Picasa's automatic photo organizer
N	PicasaNet	Hello.exe	Hello is an application that allows Blogger users to post digital photos and captions directly to their personal weblogs, or blogs
N	Pickatag	pickatag.exe	Pick-a-tag - "Freeware utility for random selection of your taglines. This utility randomly picks a tagline out of a list of taglines. It will create a signature file which your mailer can use to place under your messages"
N	PICPRTR	PICPRTR.EXE	Program for viewing and measuring a variety of 3D CAD data formats