400+ calls for a good ol' reformat. I wouldn't even try fixing that many... but if you don't want to:
Download CCleaner
Download Stinger
Download Spybot Search & Destroy
Download Avast Antivirus and scan
Download AVG Antivirus and scan.
Then you might wanna try and do a repair...
No No those are all good but do not install 2 anti viruses.