I feel your pain. About 6 months ago, I upgraded the operating system on my desktop and laptop computers to Windows XP. The moment I went on-line using AOL dial-up, I started to get these pop-ups almost constantly on both computers. I finally went into the Windows XP advanced system settings and turned something off. The pop-ups stopped immediately.
Before I wrote this reply, I was trying to remember which setting I turned off and unfortunately, I could not remember. But I do know it was an operating system change and had nothing to do with anti-virus software or even the internet software (AOL, Comcast, etc.)
I think I remember now. In Internet Explorer, I turned off some ActiveX controls to stop the pop-ups. To get to these controls, right click on the IE icon on your desktop, choose "properties", click on the "security" tab and then click on "custom level". The first 5 items are your ActiveX controls. Mine are set for prompt, disable, disable, enabled, enabled.
I believe the latest version of Internet Explorer has a built-in pop-up blocker. According to the instructions from Microsoft, the pop-up blocker can be turned on by
1. start Internet Explorer
2. On the Tools menu, point to Pop-up Blocker and then click Turn On Pop-up Blocker.