We have a page in the Guides section on how to fix all the common Quake start-up errors.
Examples:

Glide2x.dll was not found
W_LoadWadFile: couldn't load gfx.wad
Z_Malloc: failed on allocation of 3822 bytes
Could not initialize GL (wglCreateContext failed)
If you have a problem other than these and can't find the answer in the Guides section or in this Help forum, post the issue!
Examples:

Glide2x.dll was not found
W_LoadWadFile: couldn't load gfx.wad
Z_Malloc: failed on allocation of 3822 bytes
Could not initialize GL (wglCreateContext failed)
If you have a problem other than these and can't find the answer in the Guides section or in this Help forum, post the issue!