This should ring a bell to people of my generation.
I found this site by searching for a fake microsoft alert that showed up on my sons computer.
I haven't tried the solution on his computer yet since I am at my work.
It worked fine on my work laptop.
After browsing other issues on Bleepingcomputer.com I decided to register.
I use XP professional SP3 on my desktop and netbook. My son chose Windows 7 for his more sofisticated desktop.
I actually hope I don't need to post many problems.