Null src? problem

Hello everyone,
I have a quite old computer p3 833mhz but it’s fast enough to play quake3. I played about for a long time till something happend. When i start it up, q3 always shows a blue square which is showing what it’s doing. Anywayz when i reached the opengl part to start it up it shows the following error:

Initializing OpenGL driver
----- CL_Shutdown -----
RE_Shutdown( 1 )
Shutting down OpenGL subsystem
…wglMakeCurrent( NULL, NULL ): failed
…releasing DC: failed
…destroying window
…resetting display
…shutting down QGL
…unloading OpenGL DLL

Q_strncpyz: NULL src

And “Q_strncpyz: NULL src” is flickering.

I have no idea what i’ve to do…Anyone can help me?