ATI 9800 Pro Anti-Aliasing Problem

I've seen quite a few problems with AA posted here, but no one seems to have the problem I'm having. I can't get the Multisample value to change in game. It stays locked at 1 whenever I click on it. I'm running Windows 2000, DEIW 1.2. I've been keeping up with the ATI drivers. I saw there was a problem with Thief 3 and the Catalyst 4.5 drivers, so I backed off to 4.3. When I did this, I decided to try DEIW again. Lo and behold, I could change the Multisample value. So I figured it was a problem with the later ATI drivers. I didn't think anything about it until I sat down to finally play the game this morning (had it since release, been frustrated with all the setup problems, and have never got out of the first level). Once again, the Multisample value won't change. It's on 1, and that's it.

I've tried all combinations of things, from letting the AA be application set to forcing it to a value in the ATI control panel. Nothing works. Or it does the first time I try, and never again after that. I'm about to go back to 4.2 and see if that will let me keep using AA.

Has anyone else seen this? Have I missed a thread/solution somewhere in all the posts?

Thanks.