So i take it that you have at least a GeForce 6600 or an ATI X850, a CPU at 2.8gb and about 1gb memory.Because those are the minimum requirements for Gothic3. I use Razor 1911 crack:Gothic 3 v1.12 (1.12.26364.0) [EURO] Fixed Files #1. It works perfect.Install, update, backup engine.dll,game.dll and gothic3.exe. Replace files.
A description of your system would help to discover your problem. Also update your video card drivers(maybe they are too old), make sure that you are on an Windows XP with SP2 and download the last directx from microsoft(should be 9.0c february 2007).
P.S.
nboard video cards are not supported.