I would try the install with a single stick of RAM installed. You should also manually set the RAM speed, timings, and voltage to the correct values in the BIOS. How long do you wait for the system to finish the "expanding files" part of the install? I've seen a lot of people claiming that Windows 7 was "freezing" during the installation. A lot of times the only problem was that they weren't waiting long enough. There are certainly times during the installation where it appears nothing is happening.