I bought my computer from Dell about two months ago. It DEFINITELY has a valid copy of XP, which came installed on it. Brand new PC, no one has owned it before, and I have all of the paperwork.
Today my power went off, and when I rebooted the computer tried to install this on my computer. I did not allow it to install because I did not "pirate" my copy of windows, and I don't need Microsoft to try and validate this. 
In fact, I have a copy of Vista that I recieved from Dell recently to update my system, but I'm worried that if I try to install, it won't let me because of this silly error? (I'm not going to try until after Vista has been out a little longer, however.)
Any help on this? I don't want the usual answers of this not being a validated copy or that someone else must have worked on my computer because that is not the case. No one has touched this computer except myself.
Thanks.