Several years ago, I had to replace my motherboard due to a power surge that occurred during a thunderstorm.  The unprotected tv antenna wire to my tv card zapped the mb along with the tvcard.
HP wanted over $400 to replace the mb.  I replaced the motherboard myself with a different model of the same brand.  However,  HP had 'tattooed' the specific license code onto the old mb, and my undamaged HD would not work with the new mb.  I could not locate any repair shops that could tattoo the new mb, including Best Buy, Radio Shack, Circuit City.     
I called Microsoft, explained what had happened.  I provided them with the license codes off the sticker on the case and they provided me with a one time use code to activate windows XP on the new mb.   It's worked fine ever since, accepting updates, etc.  
.
Paul Hachmeyer

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