It's certainly worth a try but it would be wise to try it out locally with a friend/colleague's PC before you send it. There are BIOS and Motherboard issues but I have done similar with Win 95 and 98 on small HDs in a Grandfather Pentium and transplanted them to a similar Host.
I've never heard about the P4 problem you mention. Haven't got beyond the P3/500 MHz stage. One Day, who knows...
