Ok, this seems like a crazy idea, but I've asked crazy questions on here before and people were always helpful and never threatened to kill me, so here goes... I need advice about buying Windows (eep). I want to buy XP Pro 64bit before it becomes unavailable so I can install it on a future machine. My question though is can I buy an OEM version or do I have to buy an uber expensive version? I have no idea why there are 2 versions, I only know that OEM is something to do with system builders, but I'm not a system builder. I want to buy a PC with no OS (because where I'm buying only does 32bit versions but I have the option of no OS), and then install my 64bit XP. But there is no way I'm paying nearly £300 for that, so can I use OEM?