You might be infected. Download and run the following programs, in order:

• rkill - automatically kills malicious processes
• ESET Online Scanner - detect and remove malware
• RogueKiller - detect and remove malware
• AdwCleaner - detect and remove malware

This should remove the meat of the infection. Use Revo Portable in conjunction with a Google Search and/or information from ShouldIRemoveIt to uninstall unwanted programs.

Afterwards, reset all of your browsers to default settings: IE, Chrome, Firefox. Also, check that you do not have a malicious proxy enabled.

After removal, I recommend running a general maintenance routine at least twice a month consisting of the free versions of Malwarebytes Anti-Malware, SUPERAntiSpyware, and Spybot S&D. Remove any unwanted or unknown extensions/plug-ins/add-ons in your browsers and check your homepage and default search engine.