windows 8 Pro reboots after cold start and sleep

Hi and Seasons Greetings.
I'm having a problem with my installation of Windows 8 Pro. After a cold start or starting from sleep the system always executes a restart (error message = DRIVER_POWER_STATE_FAILURE,) then reboots and runs OK until it is switched off. This installation is a clean install on the C: partition changing from Win XP 32 to Windows 8 Pro 64-Bit. (Retail version from Microsoft on DVD)
The M/B, matched Corsair ram and processor are all new for the change to Win 8.

I have installed BlueScreenView and this pointed to the following files as potentially the problem on the last restart, but I don't know what to do about them.
1. atapi.sys
2. hal.dll
3. ntoskrnl.e

I have flashed the m/b bios with the latest version and upgraded all drivers that I can find.

Help to solve the problem would be really appreciated.

I've included the results from TSG SysInfo below. Strangely it states that Windows Defender is disabled, but Windows Defender says it is running OK.

Many thanks,

Noel.

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 8 Pro, 64 bit
Processor: AMD FX(tm)-6100 Six-Core Processor, AMD64 Family 21 Model 1 Stepping 2
Processor Count: 6
RAM: 8173 Mb
Graphics Card: NVIDIA GeForce GTX 550 Ti, 1024 Mb
Hard Drives: C: Total - 276932 MB, Free - 222952 MB; D: Total - 199996 MB, Free - 163995 MB; F: Total - 76316 MB, Free - 35225 MB; G: Total - 28597 MB, Free - 28372 MB; X: Total - 953867 MB, Free - 472993 MB;
Motherboard: Gigabyte Technology Co., Ltd., GA-970A-DS3
Antivirus: Windows Defender, Disabled

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