I used the same one I used to activate the 32bit version and when that didnt work I tried the other oem ultimate slp keys listed on this forum and they too failed. Ive even tried clean reinstalling about 3 times and still the same thing. Oddly none of the loaders activate it as well. Something very odd is going on. Edit: Turns out to be a bad bios mod. None of the listed working mods for my motherboard work for x64. Had to make a working one myself.