Thanks for the advice Mac, I'm going to take the plunge and play with my spare PC this weekend.
Ubuntu is the distro I now have, so I'll see how I get on with it.
I think I'll have to do some hardware tweaking first, mind, as I currently run the spare PC over the network, using the remote desktop. I guess a trip[ to the loft to dig out the old monitor, keyboard etc is in order first.......
VP