Persistent BSODs without a clear root cause

Welcome to SF :).
The vast majority of bugchecks point to the integrated GPU driver, igdkmd64, it's pretty recent;

Code:

lmvm igdkmd64
Browse full module list
start             end                 module name
fffff880`0504b000 fffff880`05488fc0   igdkmd64 T (no symbols)           
    Loaded symbol image file: igdkmd64.sys
    Image path: \SystemRoot\system32\DRIVERS\igdkmd64.sys
    Image name: igdkmd64.sys
    
    Timestamp:        Tue Jul 30 07:22:42 2013

Despite the date look for an update using this online utility.

• Intel® Driver Update Utility

Second place in the most blamed driver is, athrx, Qualcomm Atheros Wireless Network Adapter.
It's the latest;

Code:

lmvm athrx
Browse full module list
start             end                 module name
fffff880`06800000 fffff880`06bfb000   athrx      (deferred)             
    Image path: \SystemRoot\system32\DRIVERS\athrx.sys
    Image name: athrx.sys

    Timestamp:        Tue Jun 25 08:56:14 2013

AVG was responsible for a couple of Verifier enabled dumps, it's unfortunately known for 3rd party
A/V software to cause bugchecks.

Please remove it using the AVG Removal Tool and install MSSE as a reliable alternative.

Other DV enabled dumps DV detected Lachesis as the culprit, which is really old;

Code:

lmvm Lachesis
Browse full module list
start             end                 module name
fffff880`07e7a000 fffff880`07e81500   Lachesis T (no symbols)           
    Loaded symbol image file: Lachesis.sys
    Image path: \SystemRoot\system32\drivers\Lachesis.sys
    Image name: Lachesis.sys

    Timestamp:        Fri Oct 16 16:09:12 2009

Please update or remove the driver.

The rest of the bugcheck were all over the place, please follow the steps below to get a quick look
if the PC is overheating and to scan for possible infections.

• Download Speccy and upload a Screenshot of the summary tab.
• Download TDSS-Killer and scan for rootkits.
• Download Windows Defender Offline and scan for other types of infections.
• Download Malwarebytes FREE (uncheck the box at the end of the installation process), perform a full scan after updating the database signatures.
• Follow this tutorial on how to use the SFC/ SCANNOW tool in Windows.

Update with the results :).

Very much like before the dumps portrait the cause to be a driver misbehaving.
Please enable Driver Verifier to pinpoint the culprit(s).

Arc said:

   Information

Why Driver Verifier:
It puts a stress on the drivers, ans so it makes the unstable drivers crash. Hopefully the driver that crashes is recorded in the memory dump.

How Can we know that DV is enabled:
It will make the system bit of slow, laggy.

   Warning

Before enabling DV, make it sure that you have earlier System restore points made in your computer. You can check it easily by using CCleaner looking at Tools > System Restore.

If there is no points, make a System Restore Point manually before enabling DV.

   Tip

• If you fail to get on the Desktop because of DV, Boot into Advanced Boot Options > Safe mode. Disable DV there. Now boot normally again, and try following the instruction of enabling DV again.
• If you cannot boot in Safe mode too, do a System Restore to a point you made earlier.

Please enable driver verifier following this TUTORIAL | But using the settings below:

1. Go to Start and type in "verifier" (without the quotes) and press Enter
2. Select "Create custom settings (for code developers)" and click "Next"
3. Select "Select individual settings from a full list" and click "Next"
4. Select everything EXCEPT FOR "Low Resource Simulation", "Force Pending I/O Requests", "IRP Logging" and click "Next"
5. Select "Select driver names from a list" and click "Next"
6. Then select all drivers NOT provided by Microsoft, Unknown, or Macrovision and click "Next"
7. Select "Finish" on the next page.