I had a spoof page of AVG open when clicking on a link a couple weeks ago. It supposedly scanned my entire hard drive in about 6 seconds, found huge numbers of infections, then popped up a window that said I needed an upgrade to my AVG software with a downloadable .exe file. I shut everything down, rebooted, and ran a real AVG scan. Sure enough, there was a trojan virus called "fake warning" on my machine.