That rule has never been applied to my WIn7 Pro install disks. I have swapped between 32 and 64 bit several times over the years using the pair of disks supplied in the retail box. I've even had both installed at once (not that you can have both activativated at once).

Nah. He now has his Windows 7 back. I've made it abuntantly clear he installs 8 again at his own risk and if it goes wrong he can take it to someone and pay to have it put right. He's had Facebook withdrawl symtoms all day, but he seems happy now.

I have both Win 7 64 and 32 installed and activated - perfectly legal, as they're on the same machine and I can only use one at a time. I did check with Microsoft (and here) before I installed the 64-bit version.

In case you're wondering, I just use the 32-bit version for an old Canon slide scanner that attaches via SCSI - devil of job getting it installed there, not a ghost of a chance getting it to work on 64.