Safe XP and Game XP are two that you can get from
http://www.theorica.net/download.htm
My whole family has used these since windows 98. They are terrific. And they work
on everything from Windows 98 through Windows XP. They may work on Vista and
Windows 7 as well.
Safe XP has about 57 settings to seriously increase the performance and security
of your computer. Part of this is done by turning off many of the dangerous
services that never should have been integrated in Windows to start with.
Give them a try and leave your feedback here. I promise your computer will be a
lot faster unless you have already turned off those sevices. Even so this will
still greatly increase your security.