But really, it helps knowing what kind of system you have, especially the video card and the drivers installed: there could be some issues with this, even if your system meets the minimum requirements or is well above that. Without this info, we cannot really help you.
The 1.03 patch can be downloaded either via automatic updates: start menu> Programs>LucasArts>Star Wars Knights of the Old Republic>update Star wars knights of the Old republic or directly from LucasArts: (bigger file and longer download times depending on your internet connection since the patch is made compatible with all languages:
http://support.lucasarts.com/) )