Hmm, not working on XP? Strange, I got got it running on two XP machines here.
I just hit Act 5 NM with my Skelemancer I started months ago, really tough with all the archers and not being arsed with Dim Vision.
Tempted to continue leveling my Fury 'zon as shes at level 21 (with 18 skills points spare!)
The best thing about D2 is, there's tonnes of different specs you can do, I bought D2 on release, and D2:LoD on release and even now there's loads of different specs I haven't tried. This is my first Necromancer ever, and I've only ever tried a Bow specced 'zon and a lance spec zon back before the big jab nerf many years ago.
A single class actually plays completely differently when you spec it another way, it basically means the game has quite a few more classes than just 7!