Hey there 
Hope somebody here has some suggestions for my little problem.
Main Problem was: My pc occassionally stops working during gaming sessions. No Error Messages, just a blank screen and a loud working/fan noise from the pc.
This happened occasionally. Earlier it only happened like once a week. Now it only takes from several minutes up to a few hours.
After restart everything worked again.
From what i found out:
The Fan of my Nvidia Geforce GTX 660 isn't working properly.
Usually it should looks like this: http://img.techpowerup.org/150821/nvidia_20150821_143642.png
*Fan: 30% power -> Speed ~800 rpm -> if i open the tower i can confirm. Fan Running
But now more often it looks like this: http://img.techpowerup.org/150821/nvidia_20150821_142415.png
*Fan: 33% power -> Speed (blank) --> if i open the tower i can confirm. Not running.
The first screenshot was taken fresh after a error-induced-restart. i Assume the graphic card checks if the graphic card needs cooling and starts cooling as expected.
The second Screenshot is a few moments later.After the graphic card cooled down to around ~35 degrees it turns of the fan. (as expected)
BUT the problem is the fan doesnt restart if the temperature rises again.
After around 100 degrees (Fan still not working) the error above can be perceived. Pc turns blank. And then the fan kicks in.
I've tried:
Do you have any other suggestions?
Or is the Graphic card just broken?
Thx for reading and your help

Hope somebody here has some suggestions for my little problem.
Main Problem was: My pc occassionally stops working during gaming sessions. No Error Messages, just a blank screen and a loud working/fan noise from the pc.
This happened occasionally. Earlier it only happened like once a week. Now it only takes from several minutes up to a few hours.
After restart everything worked again.
From what i found out:
The Fan of my Nvidia Geforce GTX 660 isn't working properly.
Usually it should looks like this: http://img.techpowerup.org/150821/nvidia_20150821_143642.png
*Fan: 30% power -> Speed ~800 rpm -> if i open the tower i can confirm. Fan Running
But now more often it looks like this: http://img.techpowerup.org/150821/nvidia_20150821_142415.png
*Fan: 33% power -> Speed (blank) --> if i open the tower i can confirm. Not running.
The first screenshot was taken fresh after a error-induced-restart. i Assume the graphic card checks if the graphic card needs cooling and starts cooling as expected.
The second Screenshot is a few moments later.After the graphic card cooled down to around ~35 degrees it turns of the fan. (as expected)
BUT the problem is the fan doesnt restart if the temperature rises again.
After around 100 degrees (Fan still not working) the error above can be perceived. Pc turns blank. And then the fan kicks in.
I've tried:
- Disabling the auto-function and manually assigning more % http://img.techpowerup.org/150821/nvidia_20150821_145426.png
- Installing the newest Nvidia Driver
- Complete re-install of windows and all drivers.
- Checking the bios for some fan-Settings. But they don't change anything
- Cleaning the Graphic card (outside the tower) and re-assemble again.
- Checking if the fan is blocked - but it can be turned manually without any problem (on every restart the fan spinns on it's own - if the temperature is low enough stopping after a few spins)
- (and a few other things i can't remember right now ^^)
Do you have any other suggestions?
Or is the Graphic card just broken?
Thx for reading and your help
