While Grif has a fine list of tools to scan with, the new pests that encrypt and hold your files ransom are undone quickly by copying back from your backup.
The PC as it is means we can't ignore backups. It used to be that we might chance it but with the new pests holding files for ransom means it's no longer optional and can really upset those used to the old days.
Grif's scans are at http://forums.cnet.com/7726-6122_102-5509131.html?tag=posts;msg5509131
If you find the name of the pest that encrypted the files, then folk can research if there is a way to get files back other than backup.
Most of the emails in my father's Windows Live Mail inbox that formerly were not encrypted have mysteriously transformed to encrypted messages. He fears a virus at work, as his machine is now also running at a snail's pace. Before experiencing the problem, he'd just installed a version of Adobe Reader. Help? Any suggestions to troubleshoot/fix would be most appreciated. thx