|Download sybot and avg and scan your PC. Make sure you remove any spyware detected. This is a start but may not be the solution to your infection. Use Mozilla firefox only for browsing and not internet explorer.|
Also, when installing Spybot be sure to install the "Tea Timer" option when checking programs to install. this protects your PC realtime, from malicious spyware installing and editing your registry.
(Google "spybot search and destroy"
Google "avg free virus protection" and download/install/update/scan.)