Computer going into save mode

My computer is going automatically into save mode from the last 2 weeks, it happens anytime and i have to it shutdown to bring it back, sometimes windows restarts.

Everything is set to never in power options and automatically restart is unticked in startup and recovery options. Temperatures of hdd, gfx, processor.etc are fine. I checked hdd for errors(none found) and yet to test RAMs.

From the event viewer:

- System

- Provider

[ Name] Microsoft-Windows-Kernel-Power
[ Guid] {331C3B3A-2005-44C2-AC5E-77220C37D6B4}

EventID 41

Version 2

Level 1

Task 63

Opcode 0

Keywords 0x8000000000000002

- TimeCreated

[ SystemTime] 2012-10-21T07:00:59.256410100Z

EventRecordID 159313

Correlation

- Execution

[ ProcessID] 4
[ ThreadID] 8

Channel System

Computer Zeus-PC

- Security

[ UserID] S-1-5-18


- EventData

BugcheckCode 278
BugcheckParameter1 0xfffffa800ac2d010
BugcheckParameter2 0xfffff8800fb3c004
BugcheckParameter3 0xffffffffc000009a
BugcheckParameter4 0x4
SleepInProgress false
PowerButtonTimestamp 0



Dumpviewer says, it is caused by dxgkrnl.sys file

Can graphic card be the cause? I did remove the old drivers in safe mode with drivercleaner and reinstalled the new whql drivers but still I am getting power save mode(no BSOD).


I am using Win7 64bit Ultimate.
Here is my system config:

Intel Core i5 2500K Processor
Biostar tz68k+ Motherboard
2X 8GB 1600mhz Corsair RAM
MSI 560 GTX Non Ti Graphic Card
500 GB SATA 2 Hard drive
600W Corsair Gaming Series PSU


Except hard drive i bought the other components 5-6 months ago.

Please help  

Thanks