Debugging :: Unexpected Shutdowns On New Desktop - Event ID 41 / Task 63

Main Symptom : The new PC stops responding after several hours (sometimes a few) of intensive work and then it shuts down.Sometimes it produces a blue screen with the "critical process dies" message and sometimes doesn't.The problem was appearing also after fresh install of 2 versions of windows 7.Now in official Windows 8 it appears also.All these 3 windows versions were working fine on other desktops.

Event viewer : One critical error appears every time : Event ID 41 , task 63 , kernel-power.

Connected Peripherals :
1)Keyboard
2)Stylus pen
3)Printer
4)Wireless usb adapter
5)Stereo speakers
6)usb hub
7) four external hard disc drives

What I personally tried so far and what the technician did :

1. Tried 3 versions of Windows to see if the problem had to do with them.The problem appeared in all versions.

2. Updated all drivers and MB and VGA drivers of course.No result.

3. Ran memtest and hard disc check.No problems.

4. Disabled one of the two audio drivers ( disabled nvidia audio and left enabled the realtek audio).No result.

5. Disabled sleep.No result

6. I personally checked for 3 hours how the PC responds with only mouse and keyboard connected and without heavy use. The PC didn't crash.The technician also did the same with his mouse and his keyboard for 10 hours but without heavy use also.The PC didn't crash. The technician returned my PC and said that he couldn't find any problem in his lab and that the problem must probably have to do with the peripherals.

So when the problem really appears : The problem appears when all the peripherals are connected and after a little bit of intensive use. ( Photoshop many hours - Transfers of thousand of images from one external hard dick to the other - Printer and internet use ).

The same peripherals were used on the old PC with winxp, in the same electricity plug, and there was no problem at all.

I have spent a lot of time to understand if the problem is software or hardware related.My guess goes to a possibly problematic PSU.The PSU is Corsair 650W and new of course but i think it can't handle many peripherals and intensive use.If the problem was driver related then i guess that the crash would appear not only after heavy use but also after normal use.Another guess is that there is a problem with usb controller and that's why the peripherals that are connected via usb are causing problems,

I attach the SF diagnostic folder.