I have the same problem, 256 ram on my pc. Currently i am runing vista rtm, it works great, had to borrow from my friend 512 ram to install it. I think the problem lies in some dll file during vista installation, probably autorun.dll on vista install cd. Could anyone post a vista beta, vista rc1 or vista rc2 autorun.dll because they allow you to install it on 256 ram machine. At least i think they do.