My Acer aspire 5685 WLMi power off by itself ! Help PLZ

Hi guys , This is my first time visit this forum since my laptop have a very annoying problem .
Since the few day ago , my laptop just power off itself for no reason especially when i run any 3D game which i was able to play for hours without problem before ( Cabal online for example ) .
And now i use a program call Notebook hardware control to see its temp and unexpectedly , after i log on to any 3D game , the temp rose instantly to 80 and 95 degree just 2 min later and the laptop is not that hot at all , i checked the underneath was warm and surface was cool as normal , fans running perfectly CPU usage running with the game around 52%. Is there any thing i can do ?
Also my DVD-drive have problem with wont read any copied cd and unable to write one that apply to both DVD and CD .
I am using Vista Ultimate thought !

 

I'm assuming it could be a GPU heat/fan issue. Either the fan isn't working to dissipate the heat which could cause the machine to auto shutdown.

 

fan is running just fine , from the sound of it , also there is nothing blocking it

 

NHC can slow down your FAN Speed by controlling your BIOS.So try to uninstall NHC .