Sounds like a bug of some sort..

Do a full shutdown to stop it.
Then re start

maybe run malwarebytes
[ FREE DOWNLOAD

If malwarebytes finds malware on your system using the free one time download, that means your current antimalware protection is not effective. ]
http://www.malwarebytes.org/lp/malware_lp_form


Many of the top antivirus websites have free scanners and free cleaners to down load -
here's a top list -
http://internet-security-suite-revie...enreviews.com/

If you read up about Hijack this it should be of help, but only for experienced users