When I changed computer I also changed from Windows 98SE to XP home. I installed the MSTS on the new machine, and didn't have any problems - like others said before. Now with 3 GHz and a NVidia Geforce card it's like watching TV.
Old Goat, you mentioned hardware acceleration. I don't know Win 2000, but I think you have installed Direct-X, a program which allows to use the acceleration features of your graphics card. Perhaps it helps when you get the newest version. You can download it
from Microsoft
Unfortunately MSTS will not be developped further. Only a patch was released, updating MSTS to version 1.2. Period. I heard that Microsoft dropped all plans for a version 2. And I already hoped that finally the sound would be improved. This is by far the lousiest part of the whole package - the steam sounds are outright silly. When you are going 30 mph there are about four chuffs per second - absolutely no synchronisation with the wheel revolution. Yeecchh!
Livesteam, you can BUY lots of addiditional routes from many software firms, e.g.
3D Train Stuff . They offer the Cajon Pass, Tehachapi and now also the Donner Pass route, together with lots of engines and rolling stock.
But even better is, that through the web you can get tons of routes, rolling stock and even utilities FOR FREE. Wabash Banks already mentioned Train-Sim.com, but you'll find dozens of download places around the world. A few jewels I got are the RGS line from Ridgway to Rico, then the whole Durango - Silverton and the Cumbres & Toltec line, including K-27s, K-37s, galloping Geese and whatnot else. The mentioned Ohio River system is fantastic, too, as well as the Rollins Pass route with Moffat tunnel as well as the old line oover the pass. Of course, being a Swiss, I downloaded routes through the Alps: Gotthard Line, Rhaetian Railways, Austrian Semmering Line etc. etc.)
You could spend weeks at the computer, running all the available lines. Just take care that you still reserve a few minutes for other things like talking to people, eating, sleeping and - of course - model railroading!
Ron