At the weekend I thought I'd try and update the drivers for a GeForce FX graphics card in an old computer kicking around at home. I duly went to the Nvidia site to grab the latest driver and went through the recommended procedure of removing the old driver first, running Driver Sweeper in safe mode, and then installing the new drivers.
Cue about 6 hours of back and forth (including losing the screen completely at one point!) as I discovered that neither nVidia driver 175.19 or 175.16 worked - despite their site saying my card (5900XT) was supported!! Both of these drivers produced "device cannot start" errors when viewed in the Device Manager.
I eventually stumbled across a blog (sorry can't remember where, it was a few days ago) which stated the last driver that didn't produce this Error Code 10 (cannot start) was actually driver 169.21. So, I uninstalled (following procedure above), and installed this one and hey-presto it worked again. You can find old drivers for your nVidia card via this link http://www.nvidia.com/Download/Find.aspx?lang=en-us
I hope this helps anyone else who is Googling like I was for most of Sunday!