If you changed the motherboard for a like motherboard, you could probably still use the OEM license's number. If you changed the motherboard to a completely different one, then you will need a new license. Just the way it is.
I bought a new desktop, 3 yrs ago, with Windows XP Pro installed from the factory, and of course it was an OEM version, as usual.
The com has a MSI Intel 848P Neo Mother board which I have changed 2 times before on warranty. Now in early February this year, I had to change it again, due to one PCI slot was dead. So far everything was ok.
But, to activate the OS was now a "plenty big" problem. Somehow the technician managed to do it at his own place.
Suddenly, I was going to download a plug-in program to my Microsoft Publisher 2002, of course validation was required. No problem - I had done that several times during the last 3 yeras and everything has been ok. But not this time. Validation failed, Microsoft announced. "The Office XP Pro has to be activated, start any Office program, go to Help - activate product" - No problem, easy job. I did as told but all of the Office programs were already activated, said my com.
So I called up the Microsoft Technical Help desk, and guess if I was surprised.
The answer was very simple.
Since the beginning of this year (2007) Microsoft has started to use a new validation engine, and it tracks down on illegal copies very hard.
Depending on, the man said, If you have an OEM program, with only one licence, and major changes are made to the hardware assembly, such as changing the mother board, the OEM program then becomes illeagal. It can only be used on one computer, with the same assembly. If you then try to reinstall it you have only 30 days time to use it. Because you cannot activate a program that is already activated on another com!
If you have 2 licences, as I have on the OEM OS, it can be used twice, but no more.
So, if you have to make any major changes to your com, and the OS has only one licence it is cheeper to dump the whole com and buy a new one.
THANK YOU Mr. Bill Gates. This solves a lot of dump and trash electronic problems world wide!!!
May I compare this with the automotive world. If you buy e.g. a Ford, and the water pump cracks, you have to buy a new car, or at least a new whole engine. Only the waterpump cannot be changed.
Any one have a solution to this?