I had the same problem on an old Win2k laptop, but it was with all 2D games, not just OP2. Actually, OP2 was the most stable of them all, crashing only if I'd scroll without selecting a unit or building first. Other games would just crash before they had fully loaded. Anyways, my conclusion was crappy laptop design (AKA hardware or software problems).
Edit: Oh, and some new missions might cause OP2 to crash, but not your OS! Of course, I should mention that your sanity is never guaranteed.