Once you've started in Safe Mode and used System Restore back to a time when things were good, then I'll suggest it's a malware problem.. If you haven't already, download, install, update, then run full system scans with BOTH of the free tools below:
Malwarebytes Antimalware
SUPERAntispyware Removal Tool
Hope this helps.
Grif

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic