How do I restore my E-System Laptop to factory settings?

Can anyone tell me how I could restore my E-System laptop back to factory settings. It runs on Vista and doesn't seem to restore to basic settings as my previous Windows XP system. The reason for me doing this is I possibly recieved a virus from a bogus MSN messenger. After trying to accept a file from someone I thought I knew my computer keeps kicking me off e-mail. Also when trying to restore to a previous restore point prior to this incident, there are no recorded restore points which I know where there for sure. Any help would be appreciated. Cheers.