DNS Changer may have infected your computer unaware. Although this test isn't 100% accurate, it's your best test to let you know whether you have the virus or not. This is the DNS Changer check-up site. If the background is green, you're probably okay; if not, get help. Monday they are shutting down the servers. It explains how the FBI is going to shut down the DNS servers that are infected here.
Get it done. The page I linked to has links to help you rid your computer from the virus should you have it.