Hi,
and could I just say I much admire the brown ones? Apart from that, a 'clean' install would be to take a nice new hard drive and install a full version of Win XP Pro on it - or reformat your existing drive and get it all wiped then install. For ugrades you buy the Win XP Pro upgrade disk, and when you install it you leave your current Me or whatever drive alone, XP sort of 'converts' it to be XP Pro instead, and tries to leave all your programs etc ready installed. Obviously the 'clean' install requires you to dig out all your program disks to reinstall afterwards, and probably some of your driver disks for printers and whatnot.
A 'Clean' install tends to have few problems afterwards, 'upgrade' installs CAN (be might not) throw the odd problem up later... hence a clean install is preferred by many. If you will excuse the imagery here, if you find an etch a sketch has too many buttons, then a DIY Clean install and reinstall of all your programs etc is probably best not attempted - better to try the upgrade route, and if you hit trouble get help /advice to sort it.
Win XP Pro is great in my view, I use it on a couple of PCs and it'll be on the wife's laptop... I still have an old PC for the kids running Me, and an old laptop running 98SE, and XP Pro is far better in my view.
Dave