Glad to help if I can. Even if it doesn't work at least you'll know where to find System Restore for future reference! You can set restore points yourself (just play around). They are handy to have just in case.
First go to Start, then Programs, then Accessories, then System Tools and expand from there. S.R. should come up in a sub menu. Then follow the instructions. You can only restore where a date is "bolded".
If you find you can't do a S.R. check this: Go to Start, then Settings, then Control Panel. In C.Panel find System and click on it. Under System Properties there's a System Restore tab. Just make sure the box marked "Turn off System Restore" isn't ticked.
Finally, while restore points are created occasionally, especially if you have scans scheduled, you can always create one yourself at any time. Hope this works for you.