fixed and upgraded a friends Acer PC with a new hard drive and SSD since the OEM died, Put the same version of windows and now he's getting a windows is invalid. Well MS won't help me saying since it's OEM Acer is responsible and Acer won't even let me send a email unless I have a product under warrentee..... For out of warrentee items they send you to some hacks that charge you some outrageous price just to talk to them. God I hate prebuilts even more now, Starting to see why so many people use un-lagit copies of windows. OK rant over