This allowed the Nvidia Web Control Panel to load and allowed me to select the Web drivers in the pref panel (via Remote Access, since my displays are black), however on reboot, the displays are still black. Checking the results from running "sudo kextcache -system-prelinked-kernel" shows "NVDAStartup.kext has invalid signature; omitting." It looks like this might be the cause... not loading due to invalid signature. Any help? I'm stuck. Old late 2008 Mac Pro with Nvidia GTX 660 (which was working great up until the last Apple Security Updates.) I tried both the 343.02.03.b04 and 343.02.02f03 drivers, followed the above fix and also tried repairing permissions, but no change. System Profiler lists the two monitors plugged into the Nvidia card as (null)(null) with no Kext Loaded.
***UPDATE*** Eureka! I tried loading the "b4" driver from
http://us.download.nvidia.com/ueIQ1cKffvn8R5wGRPgpshmH1Y7hvvFn/WebDriver-343.02.03b04.pkg
previously, but it wouldn’t install, stating the build number of OS X was incompatible. I used Pacifist and the afore mentioned fix, etc., but no joy.
Then I downloaded
http://us.download.nvidia.com/dZAS8cBUHaT1cUk4pr4NBgqTMH8PbHXC/WebDriver-343.02.02b04.pkg
Which installed without a hitch. I rebooted and all is well.