BSOD randomly strikes when gaming, "ntoskrnl.exe"?

You've got it correct now.

Now you will end up with minidumps rather than kernel dumps and each new dump will not overwrite the previous dump.

For sure, uninstall AVG.
Install MSE, Microsoft Security Essentials. Link in my signature.

AVG is known to cause problems.

With the other peculiarities that you have reported, then:

HOW TO USE WINDOWS DEFENDER OFFLINE ON A USB STICK
Windows Defender Offline
· is a free standalone, bootable malware and virus remover from Microsoft.
· performs an offline scan of an infected PC to remove viruses, rootkits and other advanced malware.

Download Windows Defender Offline (about 764 kB)

You will have the choice of downloading the 32bit version (x86) or the 64 bit version (x64).
The link will help you determine whether you are running a 32 bit version or 64 bit version of Windows

NOTE!! You can download and prepare a 32 bit version using a 64 bit version of Windows
NOTE!! You can download and prepare a 64 bit version using a 32bit version of Windows.

You run the 32 bit version on a 32 bit version of Windows.
You run the 64 bit version on a 64 bit version of Windows.

The 32 bit download file name is: mssstool32.exe
The 64 bit download file name is: mssstool64.exe

For the curious, this program was originally name Microsoft Standalone System Sweeper.


INSTALLATION:
You will need an Internet Connection.
Insert 512 mB (Microsoft’s 256 mB is no longer accurate) or larger USB stick into a usb port.
Run the downloaded program--mssstool64.exe or mssstool32.exe
NEXT button
Choose the option On a USB flash drive that is not password protected
NEXT button
NEXT button
.
The install program will format the usb stick using the NTFS format.
The install program will download about 210 mB.
The install program will name the USB stick WDO_Media32 or WDO_Media64
The WDO_Media32 usb stick will have used space of 255 mB (268,140,544 bytes)
The WDO_Media64 usb stick will have used space of 282 mB (296,165,376 bytes)
You can expect the number of mB to increase as more malware appears.

UPDATE Windows Defender Offline USB stick:
· reinsert the usb stick
· run the installation program, mssstool64.exe or mssstool32.exe, again.
· the update will download about 66 mB (mssstool32.exe) and 68 mB (mssstool64.exe).

Since the malware database is sometimes updated several times in a day, always update before running.

PERFORM AN OFFLINE SCAN
Bootup your computer from the USB stick
Windows Defender Offline will automatically perform a quick scan.
After the quick scan finishes, Choose Full Scan
Select all of your drives

The initial, full scan can easily take several hours, but
Remember, your computer is being very thoroughly checked for all types of malware.

next time you want to force a crash, then please use this which is from the sysinternals folk:
http://download.sysinternals.com/files/NotMyFault.zip

Let yourself rest. Let the computer rest, especially, let the computer cool down.

Good. Take this time to fill in your system specs completely.

Update your SevenForums System Specs
User CP (located on the top menu bar) |
Your Profile | Edit System Spec (left-hand column)

To gather info, use Speccy (my favorite) or SIW or System Info

In the System Manufacturer Block, enter:
Manufacturer and Model and
ADD the word laptop, desktop, netbook or tablet.
For example:
Toshiba Satellite L305D notebook.

Provide full windows version info, for example:
MS Windows 7 Ultimate SP1 64-bit

Use the “Other Info” block for Optical Reader,
Mouse, touchpad, wifi adapter, speakers, monitor, etc

Scroll down and click on SAVE CHANGES.

You will find that in Speccy, you can select info from the display
using your mouse/touchpad and then paste that info into your specs.

SIW is a marvelous program, but the free version does not offer
this capability.

I will await your completion of post #23 before continuing.