Random screen blackout while browsing or gaming

Recently my screen has twice gone black and completely blank without warning while browsing the internet on Chrome with several tabs open; also happened a few minutes ago while playing game Crysis 2. Prior to the display going dark in Crysis 2 i updated the nVidia display drivers to the latest version. Obviously, that didn't help. There's no error message on screen and CTRL-Alt-Del has no visible effect. I pressed the Reset button on the front of the PC to force a Restart. This resulted in the usual message of Windows-didn't-shut-down-properly along with the options to start in Safe Mode, etc. I waited and let Windows start normally. As on previous occasions it booted up OK and i'm now typing this post on the PC. Should mention that the black screen has happened a couple of times over the last 10 days, and i updated the display drivers hoping that would resolve the issue, but it hasn't. Also, system fans provide adequate case cooling but are set for fairly quiet running. Temperatures have never been a problem.
System is home built approx. 7 years old:
ASUS P6TD-Deluxe Socket LGA 1366 with X58/ICH10R chipset.
Intel Core i7-965EE cpu
Noctua NH-C14 heatsink/fan
6 x 2GB G-Skill Triple channel RAM
Gigabyte GTX760 nVidia video card
Sandisk Extreme 240GB SSD
1TB HDD (TV recordings)
1TB HDD (Music)
2TB HDD (Data)
120mm Front intake fan
120mm Rear exhaust fan
140mm top vent (no fan)
Windows 7 Home Premium

There is no evidence of a BSOD occurring. Have you tried rolling back to an earlier version of the display driver?

OK, tried using System Restore. It went through the motions and Windows restarted but presented a message saying Restore to the earlier date was unsuccessful. PC ran OK for a day or two. A few minutes ago i launched a game and, after about 5 minutes of play the screen went black and ctrl-alt-del had no effect. Pressed the Reset button and PC rebooted to selection screen where i selected Start Windows Normally. When it booted to the desktop a message appeared Windows experienced an unexpected shutdown, etc. When i clicked on Details it said Problem Type: BSOD. I have attached the collected files again for your scrutiny. Does the info look any different this time?

I'll take a look at this tonight.

Did you get a chance to examine those logs?

Sorry...I forgot about that. Will look tonight.

Code:

*******************************************************************************
*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
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Use !analyze -v to get detailed debugging information.

BugCheck 116, {fffffa800e9554e0, fffff88005115ad4, ffffffffc000009a, 4}

Unable to load image \SystemRoot\system32\DRIVERS\nvlddmkm.sys, Win32 error 0n2
*** WARNING: Unable to verify timestamp for nvlddmkm.sys
*** ERROR: Module load completed but symbols could not be loaded for nvlddmkm.sys
Probably caused by : nvlddmkm.sys ( nvlddmkm+82fad4 )

Followup: MachineOwner
---------

7: kd> lmvm nvlddmkm
start             end                 module name
fffff880`048e6000 fffff880`053a9000   nvlddmkm T (no symbols)           
    Loaded symbol image file: nvlddmkm.sys
    Image path: \SystemRoot\system32\DRIVERS\nvlddmkm.sys
    Image name: nvlddmkm.sys
    Timestamp:        Thu May 28 12:19:51 2015 (5566824F)
    CheckSum:         00A7E4BD
    ImageSize:        00AC3000
    Translations:     0000.04b0 0000.04e4 0409.04b0 0409.04e4

Uninstall the video drivers completely, reboot, then reinstall them following this guide exactly:
NVIDIA Drivers - Avoid Problems