All I can suggest is getting good virus softwrae and a good pop-up blocker.
Although, you may have an Adware virus which is causing them. Could you tell me what are the nature of these adverts, what are they normally about, and which sites do you visit. Have you used P2P software recently??
Hi. My anti virus is up to date and I use good Spyware/adware removal programs. The adverts have included registry repair and poker sites. I no longer use Internet Explorer, so I don't know how they're getting through. Although I do use P2P, I haven't done so recently.
Are you using the latest version of Mozilla firefox, which is version 2.0.0.1. The 2nd version is better sercurity wise, click here - http://www.mozilla.com/en-US/firefox/