The reason I want to know is.... I have an ASUS M2n32-SLI deluxe motherboard, capable of handleing 8Gb of ram, I have just replaced the 2Gb (2x Paired 1Gb Corsair DIMM) with 4Gb (2 x paired 2Gb OCz DIMM) and the computer is not recognising the upgrade. When I go into the FAQ part of ASUS website it tells me that this happens using the 32bit edition of XP but not the 64bit. Is it possible to change mine to 64bit?? What would I have to do, do I have to buy a new edition etc????