So I have two laptops, one pretty nice one with Vista and one cheap one that I use for traveling around. I read that some people are having trouble getting TSL to run on on computers with Vista and some are having trouble running it on laptops with Intel chipsets. I think I figured out how to fix these issues.
Vista:
If you have a computer with a decent graphics card but can't run TSL with Vista, then download the 1.0b patch. I did that right away when I installed TSL for the first time and got the game running pretty well. There's still some problems though such as the game locking up on startup and during the transition in and out of cutscenes every so often. If you really want to play the game, that shouldn't be that much of a problem, just save often. If you have Vista and an Intel chipset, then read the next part.
Intel Chipsets:
After finishing the game with a light sided finish, I wanted to do a Dark Sided run through. I have cheap laptop like I mentioned before so I decided to do the Dark Sided profile on that laptop. Since my chipset, which is an Intel 945GM absolutely sucks, I couldn't run the game without any tweaking.
First I downloaded the 1.0b patch, then got 3D-Analyze (DL here). Open up 3DA, click select, find your TSL executable, and open it. Then in the "Hardware Limits (cap bits)" box, check off "emulate HW TnL caps." Click Run and you should be good to go! I haven't tried any graphics settings other than the lowest ones so far.
I hope this helps some people. Don't know if this has been posted before though so just ignore/close this thread if it has been.