Well if this is happening on multiple modules there's either something broken with your game or something wrong with your hardware. First off, just try warping back to a module you know should work (warp danm13
is the jedi enclave) and if it doesn't work I'd try just reinstalling the game, making sure you follow this
post to the letter.
Also make sure to back up your saves (C:\Program Files\LucasArts\SWKotOR\saves) before you uninstall. There's an option in the uninstall wizard but I don't trust it
Unfortunately, I can't be much more help than that I'm afraid.