If you got the mobo in the last year im sure with a bit or pursuasion the manafacturers will give you a replacement, If its the cpu, then sorry but usually you wont get another one. Do you not still have your win 7 disk?
personally because he has tried to fix it himself i doubt the manufacturer/supplier will replace the part.
always inspect your parts before you install them, if bits are missing/damaged or dont look right call the manufacture or research it.
(many places like scan.co.uk offer installation insurance cheap. bought a card reader from them and it cost 87p for instalation insurance. insurance is cheap get it then it will save you a fortune if you damage it when installing)
he dosnt need it. he can either ectract the windows key from his current installtion, by pluggin drive into another computer
or by booting it in safe mode on another computer and getting rid of old drivers so that when he puts it in new computer windows will default to trying to load it first of all with the built in generic drivers
if that fails then a simple rapair install will restore the generic drivers.
for all of you people that say this isnt possible. if it wasnt how did you install your os in the first place?