My previous phenom II x4 940 and Asus motherboard are toast, and now that I've decided on getting an Intel Core i3 2120 and a z68 motherboard, I'm not sure how intstall them and use my old hard drive (which would I guess have the old drivers still installed).
The hard drive has Windows 7 Home Premium (upgraded from Vista via upgrade disc). As another option, if I formatted the drive from another PC, could I fresh install vista then 7 and use the same product key I already have again?
You will need to reformat the hdd and reinstall Windows. When you go to put the key it and register it you may be asked to call MS and get a new key. You should not need to do Vista and then 7 again.