Hey Les,
I can think of couple of options for your case.
1- Write 2 sets batch file, one to stop the services and one to start the services, here are some help to get you started:
List of service that can be turned off:
http://www.tech-recipes.com/windows_tips1036.html
credited from the following URL:
http://www.errorforum.com/gaming-tut...-bat-file.html
NET STOP "Automatic Updates"
NET STOP "Computer Browser"
NET STOP "Cryptographic Services"
NET STOP "Diskeeper"
NET STOP "Distributed Link Tracking Client"
NET STOP "DNS Client"
NET STOP "Error Reporting Service"
NET STOP "FireDaemon Service:FAH"
NET STOP "Help and Support"
NET STOP "IPSEC Services"
NET STOP "Messenger"
NET STOP "Network Connections"
NET STOP "Norton AntiVirus Auto Protect Service"
NET STOP "Print Spooler"
NET STOP "Protected Storage"
NET STOP "Remote Access Auto Connection Manager"
NET STOP "Secondary Logon"
NET STOP "Security Accounts Manager"
NET STOP "Server"
NET STOP "Shell Hardware Detection
NET STOP "System Event Notification"
NET STOP "System Restore Service"
NET STOP "Task Scheduler"
NET STOP "Themes"
NET STOP "Upload Manager"
NET STOP "Windows Management Instrumentation"
NET STOP "Windows Time"
Option 2:
Split your hard drive and install a second operating system on it with bare bone services and with applications you want to run (I did this for my brother who wanted to run very intensive and system taxing drawing application).....the second option is a bit more work but is sure gives the horse power that your computer can offer.
Hope this helps.
Cheers