I have an older PC. I am about to install a new Motherboard and processor when it arrives next week to get ready for vista (Pentium D upgrading from P4 HT)
I heard somewhere that if ou upgrade your MB that you have to buy a new copy of XP is this true?
Does this help
Not true Kyle. Same thing happened to me but just because that was third time I did such a transition (replacing motherboard). Not sure, but I believe that you are allowed to do it three times. After that, you just call a toll-free number (MS) and explain them what you did (for example: "…my old motherboard just died and I had to replace it… so kill me…". They will give you a new number you have to register your copy of Windows with and that’s about it.
Hi Kyle,
As Sasha said, you may need to make a call to get a new #. I’m on my 5th or 6th hardware upgrade.
Unfortunately Vista may be a different story. 
Thanks everyone.