Hello all, I have another question. My laptop is a Dell xps L502x. It runs win 7 64 home. I have seen Dell win 7 64 pro disc for sale. If I wipe my hd by using a hd drive zeroing cd will it install Dell win 7 64 pro discs normally? I have the original Dell win 7 64 home disc. I have the Dell win 7 64 home disc COA at the bottom of my laptop so do I need another key to install Dell win 7 64 pro disc? I have a Win 7 64 key from a computer that has been downgraded to XP, can I use that key to install Dell win 7 64 pro disc? Thanks to all.