Take a look at
http://www.kellys-korner-xp.com/xp_restore.htm and read the article very carefully,as it is a detailed report on how to enable and disable system restore points,via editing the registry.If you don't feel confident enough to alter the registry yourself,please,please,do not do so,as one tiny mistake could cause your PC to refuse to reboot.Remember,this method of usage is ONLY intended if you wish to alter the registry yourself,without using industry software!
Best wishes,
Nez
:)