For some years, Splinter Cell: Pandora Tomorrow has been unplayable on PC due to severe graphics bugs including missing shadows and light beams, which is kinda fatal in a stealth game revolving around hiding in shadows. This year, a coder named Komat created a wrapper, which is still WIP, which fixes many of the issues.
You can download it here:
http://www.jiri-dvorak.cz/scellpt/
Sadly, it's highly unlikely we'll see an official re-release of the game for PC, but at least it's playable now.
When taking advantage of shadowmap textures supported since GeForce 3, there is a difference between DirectX8 (used by the game) and DirectX9+ in how the API expects the Z/W value at input of the texture sampler with shadowmap texture. For DirectX8 the application is supposed to provide the value in <0;2^bitdepth-1> range where the bitdepth is bit depth of the depth texture. For all other APIs the value is expected to be as <0;1>. For more info see here. It seems that starting with some version of the driver or HW, the DirectX8 path no longer comply with the original behavior and instead expects the DirectX9+ behavior.
You can download it here:
http://www.jiri-dvorak.cz/scellpt/
Sadly, it's highly unlikely we'll see an official re-release of the game for PC, but at least it's playable now.