Do NOT allow these scammers access to your computer!!!  I had just  installed Windows 7 and they called to say that my computer was downloading malware and viruses.  I though they were legit.  I did not finish with them but the one thing I did LOCKED UP MY ENTIRE COMPUTER!!!!!!  HANG UP ON THEM IMMEDIATELY! The man had an accent and said he was with WINDOWS AND WAS CALLING FROM Michigan.  I FOUND OUT THAT WINDOWS NEVER CALLS ANYONE!!!!
The number he gave me was: 888-203-7375.

The caller id said no name and no number.  The caller (who had a distinct accent, sounded like it could be from Nigeria) said that my computer that was locked up and had a really bad virus from an email.  They wanted me to give them the id number from the bottom of my computer.  I told them I didn't have time right then to do that and they wanted to call me back later when I could.  I asked for their number so I could call them back when I had time and they gave me 888-203-7375, which I didn't call back.