Whenever I open an application that requires the use of OpenGL, I always get an atikmdag.sys error. I should note that this does NOT happen with D3D apps. This has only begun occurring recently and I am unable to come up with a solution to the problem. So far I have tried the following: Reinstalling Windows (Vista SP1 x64 / Windows XP SP3 x86) Removing memory sticks Formatting drives Disabling services Bios updates / downgrades Installed / Removed windows updates Tried different driver versions Been trying to tackle this problem for a few days now without success. If anyone can help I would be grateful.