Clave: The decision to use windows is also a sane decision.
Nuke: Did you even try to activate the XP pro install on the new machine before you decided it wont work? I can almost guarantee that you'd have no problem doing it. It is only in certain circumstances where a re-activation would not work. i.e. If you attempt to activate the serial a certain number of times in one year (Six, I believe). And if it fails, a message screen should appear where it tells you to call MS and sort it out. They would certainly not be stupid enough to only allow a serial on only one hardware configuration ever. To do so would be suicide, and they know it.
Also, there are tradeoffs as to when you use alternate means of applications. Firefox is safer, but it is also inefficient, and it isnt built into the OS. WMP is pure garbage, so I have to give that one to you. But you failed in choosing WinAMP. Use VLC Media Player, instead (if you have enough power to run it, that is). MSN Messenger service sucks. Use aim, or preferably, teamspeak

.