BSoD playing certain games, various error codes (usually 0x03b)

No-one's even thinking about a reformat yet :)

As I expected, the same 2 errors are there. I'll see if I can work up a fix for you.

I've uploaded a file - msgerbs.zip - to my SkyDrive at https://skydrive.live.com/#cid=936736BB8FCEB92F&id=936736BB8FCEB92F%21526
Please download and save it.
Right-click on the saved file and select Extract all...
Change the target to C:\ and click on Extract
This should create a folder C:\msgerbs
Close all windows (it would be a good idea to print these instructions!)
Now reboot to the Repair Environment - as soon as the machine restarts, start tapping F8 - this should bring up the Advanced Boot Menu, at the top of which should be the option 'Repair my Computer'
Pick that
You'll have to log in with your username and password.
Pick the option to use a Command Prompt
At the prompt type
DIR C:\msgerbs
hit the enter key - if you get a 'Not Found' error try
DIR D:\msgerbs
or
DIR E:\msgerbs

The drive letter in use when you find the folder will need to be substituted (for<drive>) into the following command...

XCOPY <drive>:\msgerbs <drive>:\windows\winsxs /y /i /s /v /h

run the command (it should take almost no time)and when the prompt returns, type
EXIT
and hit the Enter key to exit Command Prompt - reboot to Normal Mode Windows.
Now run SFC /SCANNOW in an Elevated Command Prompt
then reboot and upload the new CBS.log file to your SkyDrive Public folder, and post a new link
Also run a new MGADiag report, and post the result.

Code:

2012-11-16 13:36:05, Info                  CSI    00000332 [SR] Beginning Verify and Repair transaction
2012-11-16 13:36:05, Info                  CSI    00000333 Hashes for file member \??\C:\Windows\Help\mui\0409\diskmgt.CHM do not match actual file [l:22{11}]"diskmgt.CHM" :
  Found: {l:32 b:Nm0jwXDzPg7+0Wb/lPzZrxe6KthUAbkrG2QotxzpUV8=} Expected: {l:32 b:Q04+9HaiDEqXWqWfSz15C0O1lwvdzRKc8OPWAuf17T4=}
2012-11-16 13:36:05, Info                  CSI    00000334 [SR] Repairing corrupted file [ml:520{260},l:56{28}]"\??\C:\Windows\Help\mui\0409"\[l:22{11}]"diskmgt.CHM" from store
2012-11-16 13:36:05, Info                  CSI    00000335 WARNING: File [l:22{11}]"diskmgt.CHM" in [l:56{28}]"\??\C:\Windows\Help\mui\0409" switching ownership
    Old: Server-Help-CHM.diskm_v.Resources, Version = 6.1.7600.16385, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral
    New: Server-Help-CHM.diskmgt.Resources, Version = 6.1.7600.16385, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral
2012-11-16 13:36:05, Info                  CSI    00000336 Repair results created:
POQ 133 starts:
     0: Move File: Source = [l:192{96}]"\SystemRoot\WinSxS\Temp\PendingRenames\598dac9e31c4cd01233b000038101403._0000000000000000.cdf-ms", Destination = [l:104{52}]"\SystemRoot\WinSxS\FileMaps\_0000000000000000.cdf-ms"
    1: Move File: Source = [l:162{81}]"\SystemRoot\WinSxS\Temp\PendingRenames\598dac9e31c4cd01243b000038101403.$$.cdf-ms", Destination = [l:74{37}]"\SystemRoot\WinSxS\FileMaps\$$.cdf-ms"
    2: Move File: Source = [l:224{112}]"\SystemRoot\WinSxS\Temp\PendingRenames\baeeae9e31c4cd01253b000038101403.$$_help_mui_0409_c7942094fabea651.cdf-ms", Destination = [l:136{68}]"\SystemRoot\WinSxS\FileMaps\$$_help_mui_0409_c7942094fabea651.cdf-ms"
    3: Hard Link File: Source = [l:250{125}]"\SystemRoot\WinSxS\amd64_server-help-chm.diskmgt.resources_31bf3856ad364e35_6.1.7600.16385_en-us_1921e36e58dca6e2\diskmgt.CHM", Destination = [l:80{40}]"\??\C:\Windows\Help\mui\0409\diskmgt.CHM"
POQ 133 ends.
2012-11-16 13:36:05, Info                  CSI    00000337 [SR] Repair complete

is the critical repair operation....
It says 'repairing 2 compnents' - but I can only see one effective repair there.

Please run another SFC /SCANNOW, and post the results, and we'll see if it did repair it or not.

Might as well :)

There's obviously something modifying that file every time.
What sort of system tweaking/optimisation tools do you have installed?
What AV are you using?