I have been told that when people go to my site, they are getting a pop up window, spoofing an error message, that says that their site has been infected by Malware/Virus, etc, and that System Security will perform a quick and free scanning of your PC for malicious programs. Here is a screenshot I got by using BrowserShots.org..
It only happens with Windows machines, and this one used IE8
I run Mac at home, and have never seen this message...
I have removed all ads from my sidebar except one that I made myself and has nothing weird in it...
If anyone can help me, I would really appreciate it. I don't even know where to begin looking!