Well a couple of days ago I posted that I'd installed 190.38 without problems. However I was wrong, and especially since I installed my new 24" monitor (wow – in widescreen HD OFF looks even more amazing!) the image is very bleached-out and shimmering. I've reverted to 182.06 and it's gone back to looking beautiful, proper colours, no shimmering. Somebody asked about rolling back drivers, and a free registry cleaner; this is the procedure I follow, using Driver Sweeper. I've pinched this text from someone else and amended it, but haven't noted who, so I'll just acknowledge their help and apologise for my inability to credit them properly.
Download and install Driver Sweeper.
Download the Nvidia driver update to the desktop or separate folder.
Go to Add | Remove Programs and uninstall the Nvidia Driver. If you have a Nvidia based motherboard be sure you select only the display driver to uninstall from the options.
Reboot when prompted. Once back to the desktop reboot again into Safe Mode.
Find and run Driver Sweeper in your Program listing, select Nvidia display (not Nvidia chipset, audio, etc.)
Once it completes, reboot again to the desktop.
Now install the new driver update from the zip file, using supplied wizard.
Once installed, set the Nvidia 3D settings in the control panel, save and exit (I use Fortiesboy's settings, thanks very much)
Start OFF and in Workshops click on the Graphics button to let it configure the game to your video card, then choose Custom to set your resolution and AA level.
And, er, yes, in future I'll try to resist fiddling about with "latest drivers" until the "all clear" is sounded by the Wise Men!