new motherboard
new cpu
new HDDs
I'd call that a new computer. I could understand MS not activating the OEM license on a different computer.
Here in the UK, there's a well-known joke from a TV sitcom - a guy claims he's had the same sweeping brush for 20 years. He says 'of course in that time, I've had 4 new heads and 3 handles'. (Only Fools and Horses)
MS's definition of a new computer for licensing purposes is simply the motherboard - other changes can cause demands for re-activation(most notably the MAC address of a network connection) but will almost always be allowed.
FYI
I upgraded my motherboard & processor from Intel DX58SO/i7-930 to Intel DX58SO2/i7-980x and activated via telephone without any issues. After I read the installation ID, the automated system asked, "on how many computers is this OS installed?" I answered one and the automated system indicated everything was OK.
So, upgrading the motherboard and processor with an installed OEM Win 7 is not an issue as long as it's only installed on one computer. They likely keep track of how many times this is done and if it gets excessive, I'm sure you'd have to speak with a live MS representative and explain.
I didn't do a clean OS install. It took too much time just to swap the hardware and clean-up all the dust that had accumulated since I last cleaned the system case last year.
Regards
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