W2K was always MUCH slower to start up / shut down than XP.
Even with a clean rebuild W2K would be slow to start.
I run a PIII 600 desktop with XP, and it is more than acceptable.
The only downsides with these older laptop PCs tends to be the capacity and speed of the HD (which is easy enough to upgrade in a laptop) - and the graphics (which isn't).
SD