Not quite like this. And why would Microsoft call and tell you specifically there was an issue? Wierd.
But for the last two days my PC would not boot Internet Explorer. I did what you did and removed my downloads and did a cleanup scan and I'm back in business.

I am not a computer geek by any means but I had the same thing pop up that clem did once. It sure wreaked havoc with my pc but I did get it fixed. It was a virus that was coming thru the cable.. lol. I kid you not. Our local cable company had something to do with it. lol.. I never open anything unles I check it out thoroughly first..