I recently had to upgrade my OS to 64-bit XP Pro. I installed my SA and it works. I decided to try it out so I booted up SA and the started playing. The game is basically unplayable. It's hard to explain but when I play it, The game runs fast, then slow, then normal speed in random order. For example, it plays normal for a few seconds, then speeds up(like with SPEEDITUP) for a few second or slows down(like SLOWITDOWN) in random order. So I call this horrible lag. While I played it with the Fraps FPS count on, It was always reporting 150 - 200 fps with the lag. It is supposed to be 150 - 200 fps because of VSync being off. Tried turning it on, still same problem except Fraps shows 60 fps(60 refresh rate). Tried FL ON, still the same problem with 25 fps. Tried both on, still the same problem. I also tried playing around in the nVidia control panel, still having this weird problem. I upgraded my Video card drivers are up to date(I checked). Mobo drivers up to date and CPU up to date. Don't know what the problem is so plz help me. Thanks.