In the battle against spyware and viruses, it is often necessary to close down programs that are running using the task manager. It’s hard to know what to close down unless you know what the essential Windows processes are. Almost all viruses, and much of the spyware will automatically put themselves back into startup when you remove them if you leave them running in the background.
In Windows 98/ME you only need to leave Explorer and SysTray running.
Here is a list of processes in XP that are essential:
svchost.exe – a few
System Idle Process
Likely you will have a few svchost.exe’s running. Some of these can be shut down, but it’s hard to tell which ones. I usually leave them alone.
This is a generic list of essential processes. You will probably have other things running as well, but almost all of those can be closed with no problem. They’ll come back on bootup anyway.
I almost always close all non-essential processes down before I change Windows startup. That way nothing is memory-resident and can reload itself after I’ve taken it out out of the registry.