Originally Posted by mep916

You'll probably need to purchase a new OS.

Originally Posted by Nvidia4life

You can't reinstall a factory installed Vista copy on a new motherboard. If you try to reactivate, you will have to pay for the activation. You can only uninstall and reinstall on a new mobo if you purchased the OS seperately. The preinstalled OS is linked to your mobo.
That is the way people get ripped off when they buy a manufacturer's PC. Good for you for getting away from that. It is a good price up front when you buy one, but it's a rip off when you compare how easy it is to upgrade home-built computers to your personal specs.

Originally Posted by [-0MEGA-]

Usually if you use the CD/DVD that came with a pre-built computer such as his HP, then it is only good on an HP machine. It ties into HP's compatible motherboards and makes sure it's being installed on an HP system, so if you install it on say an Asus board, it most likely won't work.

If it's an OEM/retail copy, all you have to do is call up Microsoft, tell them you replaced the motherboard and need to reinstall, then they will give you a new activation key.