Also try rebooting your computer and do a complete defrag.
If you haven't noticed, when your game crashes to desktop, you'll see a yellow triangle with an exclamation mark lower right corner. It's saying your Virtual Memory is low. SW:KOTOR has a memory leak in it if you are using Windows XP and you have the Service Pack 2 SP2 update installed. This is pretty much common knowledge.
Advice, make about 3 different saves. Your save can become corrupt and then you are really in a world of hurt.