I'm still having problems with this: the 64-bit disc is being reported as the setup.exe not being a valid Win32 application. There was also another message saying the disc isn't compatible with the operating system. We've tried booting with the disc in and also booting up and then putting the disc in (following 2 different sets of instructions, one from the MS website and the other from the booklet which came with the disc).
The BIOS is ok, set to boot from the CD/DVD drives first. The 32-bit disc boots as you would expect.
Obviously doing something wrong, but can anyone help before murder happens in this household?