I had a problem with my security manager on my laptop, and after my computer rebooted, I was told to reinstall XP. The computer automatically reinstalled the OS, which came preinstalled on the computer. After installation was complete, I was told to reactivate. When I tried to do so, by entering the key on the certificate of authenticity on the bottom of the laptop, I received the message that the key was not valid. I even tried to activate by phone, but the key issued was said to not be valid. There has been no new hardware installed or major changes to the computer. I called Microsoft, who told me to contact Compaq. They in turn told me that since the computer was out of warranty, they would have to charge me, but they also referred me to this site. Can anyone out there help since I do not want to have to go out and buy software for a computer that was issued to me? Thanks.