If XP was native on the system then the hardware is just as old. XP was back in the dialup days. So you're dealing with a single core cpu's, low memory, 10/100 nic cards, usb 1.0/2.0, Some mobo's with only IDE and no sata, older bios, older drivers. You're really missing out on a lot of performance these days. I would retire that old XP to linux and start tinkering on it and build a NEW dekstop system with windows 7.
Absolutely. The hardware will be replaced. I guess I should have it clear that I will be getting all new hardware. I do have one very old HP 5000 laser printer and one newer Epson 845. The HP was been an amazing workhorse, but needs to be retired. The Epson is a piece of junk and will be replaced.
Any special reason you prefer Win 7? I really don't mind having to learn a new UI as long as it's really better. I'll have to do it eventually, so might as well bite the bullet while I am doing a lot of other upgrades.
I'm no alpha techie, so really have had no intention of tinkering with Linux. But that has been suggested so many times, that I might just have to give it a try in my unlimited free time. :-)