You're crazy lol. But I'm little crazy too I have one desktop and one 11 years old laptop.
It's helpful having more than one PC, because of one dies, you've got spares. If my 2500K rig were to die for any reason, I can use the Core 2 Quad until I can get a replacement rig.
Just installing XPx64 on the 3700+ rig now. I had to remove and reinstall the IDE cable from the drive and motherboard because for some reason my DVD drive wasn't being detected but now it is. I'll have to run the benchmark with the side panel removed, just in case the CPU gets too hot.
I've tested the app in XPx64 in a VM by the way, works OK in case you were wondering.