je ne comprend pas de l'aide svp

bonjour

je venez d'installer la demo de quake 4 quand il me dit quand je le lance " desktop must be in 32 bpp mode" puis il me met sa

execing 'specs/recspec.dat'
execing 'specs/recspec_cpu.dat'
execing 'specs/recspec_gamedetail.dat'
execing 'specs/recspec_gpu.dat'
execing 'specs/recspec_gpudetail.dat'
execing 'specs/recspec_lighting.dat'
execing 'specs/recspec_foliage.dat'
Vendor:10DE Device:01DD
execing 'specs/recspec_gpu.dat'
execing 'specs/recspec_gpudetail.dat'
execing 'specs/recspec_foliage.dat'
Initializing OpenGL subsystem
********************
FATAL ERROR: Desktop must be in 32 bpp mode.
********************
--------------- BSE Shutdown ----------------
---------------------------------------------
Shutting down OpenGL subsystem
...releasing DC
...resetting display
...shutting down QGL
idRenderSystem::Shutdown()
Shutting down performance queries
Desktop must be in 32 bpp mode.


merci svp de me dire quoi fiare pour jouer