It's a malware infection, use the following free programs, download, install, update and reboot into Safe Mode to remove:
Remove Restrictions Tool:
http://www.softpedia.com/progDownload/RRT-Remove-Ristrictions-Tool-Download-68926.html
Download from Softpedia Secure Download (RO), install, run and check all boxes then click Apply and then reboot. This tool re-enables what codecs/viruses have disabled.
Malwarebytes Anti-Malware:
http://www.download.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html?hhTest=1.
Select Full Scan.
Remove all infections that it finds after scan.
SUPERAntiSpyware Free Edition:
http://www.download.com/SUPERAntiSpyware-Free-Edition/3000-8022_4-10523889.html
Select Scan your Computer, select your drive and select Perform Complete Scan and remove infections, then click on Preferences, click Repairs Tab and click on any of the System and Browser Repair Items that you may have problems with then click Perform Repair.
Comodo BO Clean:
http://www.comodo.com/boclean/CBO_download.html
Simply download and install, follow instructions on screen.
Real time virus and malware protection - stops rootkits,, hijackers, keyloggers and Trojans from stealing your identity.
Go here to see what it protects you against:
http://www.comodo.com/boclean/trolist.html