One of a new problem that you will experience in Windows Vista and Windows 7 but not on Windows XP is the screen going black for a few seconds and then comes back on with a popup notification telling you “Display driver stopped responding and has recovered. Display driver nvlddmkm stopped responding and has successfully recovered.” From the message it does seemed like the driver has crashed and most of the time neither upgrading nor downgrading the driver will fix the problem. If you search for this error in Google, you will probably end up with hundreds of threads to read and with some really ridiculous suggestions such as reformatting your computer, sending back the graphics card to manufacturer, etc.
The good news is you don’t have to go through that because someone has already went through all the hard work which he finally found a workaround that fixes the problem and shared it in NVIDIA forums. Thanks to FunkY for finding that as well and posting it in our forums to help BigGuy.The simple trick is to set a fixed graphics card for PhysX processor instead of letting it auto select which may end up selecting your CPU and causing the crash. Go to Control Panel > NVIDIA Control Panel > Expand 3D Settings > Set PhysX configuration. At the select a PhysX processor, by default the “Auto-Selected (recommended)” setting is selected. Click on the drop down menu, select your graphic card and click the Apply button to confirm the changes.
This simple solution should be your first attempt to fix the problem before reinstalling drivers, replacing nvlddmkm.sys driver file, fixing registry, uninstalling windows patches and etc.