Windows 7 Freezes

Definitly unlikely. But maybe it is "bad", as you said.
Though, how to check? Use an other installation DVD? That could cost a lot, and might not even give results.

True, trouble for my mate is that this is a customers machine. So buying another retail copy even OEM would have to be a very last option.

Given the fact that a few have posted on here with freezing issues, there's clearly something happening, but what.

Have the computer and/or the installation DVD checked by Microsoft?

Would they even do that? If they did, I'd bet it would be even cheaper just to get a new copy of Windows 7. They would probably make your life hell as well.