Have you ran a scan with your Anti-Virus Program??
Here are a few more suggestions:
AVG(free) might be able to fix it. Be sure to update it before you scan your computer:
AVG Free Advisor: AVG Anti-Virus Free, then follow the prompts.
Nod32 - Free Virus Scan: Use ESET's Online Antivirus Scanner
After you run these AV Programs you can Delete them if you so choose.
Post back if the problem persists.
