1. Restart.
2. Scan with an Antivirus client. If you don't have one, download
AVG, install it and update it. Then scan your machine. If it doesn't find anything, restart, then scan again. If it doesn't find anything still, boot into
safe mode and scan again.
3. Download
Spybot S&D, update it and scan.
Some quick Googling makes it seem like you have some malicious software on your computer.