Published: Dec. 7, 2004 at 4:46 PM CST|Updated: Jan. 21, 2006 at 11:04 PM CST
Chances are, your computer is infected with so-called "Spyware" and "AdWare". The best tools to detect and remove the unwanted software, are Spybot Search and Destroy, and LavaSoft's Ad-Aware. Each has its own strengths, and both are free. It's suggested you download and install both, and run them on a regular basis.