I have found that system restore doesn't always create a restore point for each day. Have you checked your settings? Right click on my computer then properties. Go to the system restore tab and see what is listed.
I tried to restore my system to a previuos date and restore would not complete. Said system could not be restored no changes made. Tried several resotre points with no luck. Ran SFC to see if that would help by still will not restore. I am runing XP home edition with SP1. Any ideas on how to get resotre working again?