I just formatted one of the client's PC and installed Win98SE again as the license is indeed for this OS. Set the drivers, updated all patches and installed all other softwares. While closing the casing, here's the horror part!!! Thats not the case for the PC I've just fixed!! : ( So in other words, I have used a wrong product key when the original casing was lying not too far away. Is there anyway to change the product key now as I don't want to go through the whole process of re-installing again please?