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.

X	I-Worm.GiGu	uGiG.eXe	Added by the GINK WORM!
X	I386	I386.exe	Added by the MYPOWER WORM!
?	I81SHELL	I81SHELL.exe	Appears to be related to drivers for an Intel 810 graphics chipset on an ASUS motherboard
U	i8kfangui	i8kfangui.exe	Graphical interface for fan speed control
U	IAAnotif	iaanotif.exe	IAA Event Monitor User Notification Tool - part of Intel® Application Accelerator - "a performance software package for desktop PCs using select Intel® chipsets" that "replaces the ATA drivers that come with Windows with drivers optimized for desktop and mobile PCs." If you use the RAID version it's required to notify you if a RAID 1 disk has failed
Y	iamapp	iamapp.exe	AtGuard personal firewall engine. As Atguard was bought by Symantec some time ago, it's now the Norton Personal Firewall executable as well
X	Iamnacho On Irc.MusIrc.com Is a Homosexual!	XBox64.exe	Added by the RANDEX.Y WORM!
?	Iap	iap.exe	Possibly part of Dell OpenManage Client Instrumentation - software that allows remote management application programs to access information about, monitor the status of or change the state of the client computer, such as shutting it down remotely?
X	IASHLPR	IASHLPR.EXE	Added by the OPASERV.T WORM!
?	IBM Warranty Notification	ERTS0749.exe	IBM Warranty Notification - presumably it's a reminder to either register or that warranty is about to expire?
N	ibmmessages	ibmmessages.exe	Allows IBM to push messages onto users' computers. Quote: "The Access IBM Message Center can display messages to inform you about software and solutions available from IBM as well as messages from IBM eSupport"
?	Ibmmon.exe	Ibmmon.exe	??
U	Ibmpmsvc	ibmpmsvc.exe	Power management driver for IBM laptops. Provides support for the use of four keys on the thinkpad keyboard with blue key tops - Fn, F3, F4 & F12 - which have specific functions to control the standby and hibernate buttons. Not required if you don't plan to go into standy or hibernate modes
U	IBMUltraBayHotSwapCPLLoader	IBMBAY2N.EXE	Supports hot swapping in Thinkpad UltraBay Option on IBM ThinkPad laptops
?	IBMUltraBayHotSwapSound	IBMBAYSN.EXE	Supports hot swapping in Thinkpad UltraBay Option on IBM ThinkPad laptops. Is it needed though - does it just play a sound?
X	icdd7ee6	rundll32.exe [path] icdd7ee6.dll, EnableRunDLL32	LZIO.com adware downloader
N	ICH Synth	eusexe.exe	Sound related and can be disabled without affecting performance although advanced sound features may be sacrificed. May be related to Compaq PC's with "SoundMAX integrated Digital Audio" (Analog Devices Inc.) devices
U	iClean	iClean.exe	IEClean - "advanced, comprehensive package of tools which perform a number of functions to allow you to control your online privacy"
N	iCn	NAG.EXE	iChoose - shopping browser enhancement that alerts you to cheaper deals for goods you want to buy, if they exist
N	ICO	ICO.EXE	Found on a Sony Vaio laptop and seems to be related to Mouse Suite 98 Daemon according to the properties. Appears to cause a behaviour where the desktop suddenly flips back up when playing DirectX associated games
N	Icon Animation	HDE.EXE	Part of McAfee Nuts & Bolts. Provides entertaining animation of your desktop icons
N	Icon Hearit 95	hearit95.exe	Audio desktop customization utility from Moon Valley Software. Resource hog
N	Icon Hearit 98	hearit98.exe	Audio desktop customization utility from Moon Valley Software. Resource hog
X	Icon lptt01	icon.exe	Variant of the RapidBlaster parasite (in an "Icon" folder in Program Files). It is not recommended you manually uninstall RapidBlaster but use RapidBlaster Killer - see here
X	Icon ml097e	icon.exe	Variant of the RapidBlaster parasite (in an "Icon" folder in Program Files). It is not recommended you manually uninstall RapidBlaster but use RapidBlaster Killer - see here
Y	ICONCLNT	iconclnt.exe	APC PowerChute Tray Icon. Associated with the UPS listing
U	ICONDESK	ICONDESK.EXE	Small utility which will allow you the option of hiding or showing your desktop icons
N	Iconfig.exe	Iconfig.exe	Icon for LS-120 "Superdisk"
X	iConfigLoader	DIIhost.exe	Added by the GAOBOT.AO WORM!
N	Iconoid	Iconoid.exe	Iconoid is a desktop icon manager
N	Iconsaver	Iconsaver.exe	IconSaver is a desktop icon manager
X	ICQ Center	[path to worm]	Added by the RANDIN WORM!
X	ICQ Hacking Pro	ICQpro.exe	Added by a variant of the NETSPY TROJAN!
N	ICQ Lite	ICQLite.exe	ICQ Lite - compact version of the popular messaging program
X	ICQ Lite Messenger	[random filename]	Added by an unidentified VIRUS, WORM or TROJAN! Unlike the legitimate ICQ Lite executable, which will be located in the ICQLITE folder in Program Files, this particular impostor is located in the Windows or WinntSystem32 directory
X	ICQ Net	winlogon.exe	Added by variants of the NETSKY WORMS! Note - this is not the legitimate winlogon.exe process which should NOT appear in Msconfig/Startup!
N	ICQ Plus	vplus.exe	ICQ Plus is a freeware utility makes your ICQ skinnable (change the look). Available via Start -> Programs
U	ICSDCLT	rundll32.exe Icsdclt.dll, ICSClient	Internet Connection Sharing allows more than one computer to simultaneously access the internet with a single connection. Also required when networking two machines
N	ICServer	Icserver.exe	Intel Intercast viewer software. Gives access to selected internet pages which are broadcasted by several TV stations
Y	ICSMGR	ICSMGR.EXE	Monitors DNS and DHCP requests for ICS (Internet Connection Sharing). Needed if you’re sharing the internet on various computers
N	IC_KEY_3	spvic.exe	Instant Chess related
N	ID Commander	IDCom.exe	Caller ID utility for identifying incoming telephone numbers
X	ID8525	ID8525.exe	Added by the ID8525.A TROJAN!
X	ID8525	id85255.exe	Added by the ID8525.A TROJAN!
?	IDA	IDA.EXE	HP related - in a Program FilesHewlett-PackardPC COE folder
X	IDE	ide.exe	Added by the ASSASIN.F TROJAN!
X	IDE Loader	IDElibr32.exe	Added by the XILON TROJAN! Related to the game "Diablo II"
X	idecntl	idecntl.exe	Added by a variant of the CRYPTER.C TROJAN!
U	iDesktop	idesktop.exe	Immersion TouchWare Desktop software for devices such as the Logitech iFeel Mouse
N	IDMan	IDMan.exe	Internet Download Manager - download files faster, schedule and resume
N	IDW Logging Tool	idwlog.exe	Added with WinXP SP1. Usually only found in internal builds only to indicate the current build being used. Can cause slow network logon problems
U	IE Doctor	IEDoctor.exe	IE Doctor Toolbar - "IE Doctor can help you to Repair IE easily, protect IE and OE from all malicious changes. It can Repair the HomePage, context menu, IE toolbar button, startup items, Favorites, typed URLs and the entire Internet Options"
X	IE Menu Extension toolbar	rundll32.exe [path] tbextn.dll DllShowTB	Topconverting.com/180Search "IEMenuExtension" toolbar
N	iecheck	iecheck.exe	Integrity checker for IconEdit2 icon editor. It serves for IconEdit2 internal tasks only and can be safely deleted from the system if you are running the latest version of IconEdit2
U	IECleanAux	Ieboot6.exe	IEClean by Kevin McAleavy - cookie manager, cache cleaner, history cleaner, etc. Performs cleaning tasks at startup
X	iedll	iedll.exe	Homepage hijacker, redirecting to coolwwwsearch.com
X	IEDriver	IEDriver.exe	Installed as part of adware (Cydoor) based peer-to-peer file sharing software called URLBlaze
X	IEDriver	xplore.exe	IEDriver adware variant
X	IEDriver	TD.exe	IEDriver adware variant
X	IEengine	IEeng.exe	STARTPAG.AI hijacker
X	IEFeatures	IEFeatures.exe	Added by the POPMON.A TROJAN! - also known as PopMonster adware
X	IEFeatures	Internetfeatures.exe	Added by the POPMON.A TROJAN! - also known as PopMonster adware
X	Iehelper	syslaunch.exe	Outwar adware downloader
X	iel2cde8	rundll32.exe [path] iel2cde8.dll, EnableRunDLL32	LZIO.com adware downloader
X	IELoader32	iexplore32.exe	Added by the SPEX or SPEX.B WORMS!
X	Iesar	Iesar.exe	Browser hijacker - redirecting to an adult web page
X	Iesearch.exe	Iesearch.exe	LookNSearch adware
X	iestart	iexp1orer.exe	Added by the NEMOG.C TROJAN!
N	ietsr	ietsr.exe	IEClean by Kevin McAleavy - cookie manager, cache cleaner, history cleaner, etc
X	ieupdate	MCP****.exe [**** = random char]	Added by the ASOXY TROJAN!
X	ieupdate	mcpdll32.exe	Adware downloader trojan
X	Iexplore	iexplore.exe	Added by the BOXER TROJAN! Note - this is not the legitimate Internet Explorer (iexplore.exe) process, which should not appear in Msconfig/Startup unless you add it manually!
X	IEXPLORE	iexplore.exe	Added by the APHEXDOOR TROJAN! Note - this is not the legitimate Internet Explorer (iexplore.exe) process, which should not appear in Msconfig/Startup unless you add it manually!
X	Iexplore Services	iexplore.exe	Added by an unidentified VIRUS, WORM or TROJAN! Note - this is not the legitimate Internet Explorer (iexplore.exe) process, which should not appear in Msconfig/Startup unless you add it manually!
X	iexplorer lptt01	iexplorer.exe	Variant of the RapidBlaster parasite (in an "iexplorer" folder in Program Files). It is not recommended you manually uninstall RapidBlaster but use RapidBlaster Killer - see here
X	iexplorer ml097e	iexplorer.exe	Variant of the RapidBlaster parasite (in an "iexplorer" folder in Program Files). It is not recommended you manually uninstall RapidBlaster but use RapidBlaster Killer - see here
U	IFSplash.exe	IFSplash.exe	I-FORCE driver for force feedback steering wheel
N	igfxtray	igfxtray.exe	Quick access to the control panel via a System Tray icon for graphics based upon the Intel chipsets (ie, i810). These chipsets are often included on motherboards. Available via Start -> Settings -> Control Panel
X	igsex2x	igsex2x.exe	NewDial premium rate adult content dialler
X	iilc	IILC.EXE	Homepage hijacker
X	Iinl	iptl.exe	PurityScan/Clickspring adware
N	iIWiper	Systemwiper.exe	System Wiper from iI Software - allows you to clear the history of your activites from you computer. Run manually on a regular basis
Y	IJ75P2PSERVER	IJ75P2PS.EXE	Printer utility which is required in order to make the printer work correctly
Y	IKE Service 95	IKEService.exe	Associated with PGP. The PGP Tray can be disabled, but without IKESERVICE you won't be able to de- or encrypt anything
U	iKeyWorks	IKEYMAIN.EXE	A4Tech wireless keyboard driver and utility
X	iLLeGaL	Mplayer.exe	Added by the HOLAR.C (or GALIL) WORM! Note - this should not be comfused with Windows Media Player which has the same filename
X	iLLeGaL.exe	Mplayer.exe	Added by the HOLAR.C (or GALIL) WORM! Note - this should not be comfused with Windows Media Player which has the same filename
?	ILO_Office_Manager	IntEdReg.exe /OFFMAN	Intense Educational Ltd - Language Office Software. Is it required?
U	iLyric	iLyric.exe	iLyric plugin for Winamp media player. Allows you to retrieve the lyrics for your songs with the press of a button
N	iM Start Center	iM_Tray.exe	Installed with the Sound Blaster Audigy range of soundcards. A radio tuner installed if the user chooses during installation. Available via Start -> Programs -> iM Networks -> iM Radio Tuner
X	Image	rundll32 image.dll, Install	CoolWebSearch parasite variant