Shoutbox

With the right tweaks XP can run on a P-100 without issues.  Granted XP will be slow on anything under 500MHz but it's bearable.  2000 Workstation would probably be a better choice performance wise while XP will give you better looks and a few extra features.

On the flipside of the coin, you should start to think of upgrading even to older equipment like a Athlon 800MHz+ or Pentium3 800MHz+ as that will get XP running smoothly and enable you to do more.