Hello,
I think it's a good idea to run a Video Stress Test since few crashes are pointing to ATI Display drivers as well 
 
FurMark: Graphics Card Stability and Stress Test, OpenGL Benchmark and GPU Temperature | oZone3D.Net 
   
 FurMark Setup:
- If you have more than  one GPU, select Multi-GPU during setup
- In the Run mode box, select  "Stability Test" and "Log GPU Temperature"
Click "Go" to start the  test
- Run the test until the GPU temperature maxes out - or until  you start having problems 
(whichever  comes first).
- Click "Quit" to exit
Try this  free stress test:  
Free Software - GIMPS
   
 Prime95 Setup:
-  extract the contents of the zip file to a location of your choice
-  double click on the executable file
- select "Just stress testing"
-  select the "Blend" test.  If you've already run MemTest overnight you  may want to run the "Small FFTs" test instead.
- "Number of torture  test threads to run" should equal the number of CPU's times 2 (if you're  using hyperthreading).
The easiest way to figure this out is to go to Task  Manager...Performance tab - and see the number of boxes under CPU Usage  History
Then run  the test for 6 to 24 hours - or until you get errors 
(whichever comes first).
The  Test selection box and the stress.txt file describes what components  that the program stresses.
Bughceck:
	
	
	
		Code:
	
	
		SYSTEM_THREAD_EXCEPTION_NOT_HANDLED_M (1000007e)
This is a very common bugcheck.  Usually the exception address pinpoints
the driver/function that caused the problem.  Always note this address
as well as the link date of the driver/image that contains this address.
Some common problems are exception code 0x80000003.  This means a hard
coded breakpoint or assertion was hit, but this system was booted
/NODEBUG.  This is not supposed to happen as developers should never have
hardcoded breakpoints in retail code, but ...
If this happens, make sure a debugger gets connected, and the
system is booted /DEBUG.  This will let us see why this breakpoint is
happening.
Arguments:
Arg1: ffffffffc0000005, The exception code that was not handled
Arg2: fffff88005a89cad, The address that the exception occurred at
Arg3: fffff880079059b8, Exception Record Address
Arg4: fffff88007905220, Context Record Address
Debugging Details:
------------------
EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".
FAULTING_IP: 
atikmdag+267cad
fffff880`05a89cad 48894808        mov     qword ptr [rax+8],rcx
EXCEPTION_RECORD:  fffff880079059b8 -- (.exr 0xfffff880079059b8)
ExceptionAddress: fffff88005a89cad (atikmdag+0x0000000000267cad)
   ExceptionCode: c0000005 (Access violation)
  ExceptionFlags: 00000000
NumberParameters: 2
   Parameter[0]: 0000000000000000
   Parameter[1]: ffffffffffffffff
Attempt to read from address ffffffffffffffff
CONTEXT:  fffff88007905220 -- (.cxr 0xfffff88007905220)
rax=57fd3a610b3358f4 rbx=0000000000000000 rcx=fffffa8009a4a8b0
rdx=fffffa8009a4a740 rsi=0000000000000004 rdi=0000000000000000
rip=fffff88005a89cad rsp=fffff88007905bf8 rbp=cccccccccccccccd
 r8=fffffa8009a43020  r9=0000000000000140 r10=fffffa8009a4a740
r11=0000000000000000 r12=00003474d4d0ac6f r13=0000000000002f8c
r14=0000000000000020 r15=0000000000000000
iopl=0         nv up ei pl nz na pe nc
cs=0010  ss=0018  ds=002b  es=002b  fs=0053  gs=002b             efl=00010202
atikmdag+0x267cad:
fffff880`05a89cad 48894808        mov     qword ptr [rax+8],rcx ds:002b:57fd3a61`0b3358fc=????????????????
Resetting default scope
CUSTOMER_CRASH_COUNT:  1
DEFAULT_BUCKET_ID:  VISTA_DRIVER_FAULT
PROCESS_NAME:  System
CURRENT_IRQL:  0
ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".
EXCEPTION_PARAMETER1:  0000000000000000
EXCEPTION_PARAMETER2:  ffffffffffffffff
READ_ADDRESS: GetPointerFromAddress: unable to read from fffff800030c50e0
 ffffffffffffffff 
FOLLOWUP_IP: 
atikmdag+267cad
fffff880`05a89cad 48894808        mov     qword ptr [rax+8],rcx
BUGCHECK_STR:  0x7E
LAST_CONTROL_TRANSFER:  from fffff88005a89e47 to fffff88005a89cad
STACK_TEXT:  
fffff880`07905bf8 fffff880`05a89e47 : fffffa80`09a57670 fffff880`05df65a0 00000000`00000027 00000000`00001f38 : atikmdag+0x267cad
fffff880`07905c00 fffffa80`09a57670 : fffff880`05df65a0 00000000`00000027 00000000`00001f38 00000000`000041ed : atikmdag+0x267e47
fffff880`07905c08 fffff880`05df65a0 : 00000000`00000027 00000000`00001f38 00000000`000041ed fffff880`05a873f2 : 0xfffffa80`09a57670
fffff880`07905c10 00000000`00000027 : 00000000`00001f38 00000000`000041ed fffff880`05a873f2 fffff880`05df65a0 : atikmdag+0x5d45a0
fffff880`07905c18 00000000`00001f38 : 00000000`000041ed fffff880`05a873f2 fffff880`05df65a0 cccccccc`cccccccd : 0x27
fffff880`07905c20 00000000`000041ed : fffff880`05a873f2 fffff880`05df65a0 cccccccc`cccccccd 00000000`00000004 : 0x1f38
fffff880`07905c28 fffff880`05a873f2 : fffff880`05df65a0 cccccccc`cccccccd 00000000`00000004 00000000`00000000 : 0x41ed
fffff880`07905c30 fffff880`05df65a0 : cccccccc`cccccccd 00000000`00000004 00000000`00000000 fffff880`03163180 : atikmdag+0x2653f2
fffff880`07905c38 cccccccc`cccccccd : 00000000`00000004 00000000`00000000 fffff880`03163180 00000000`00004d78 : atikmdag+0x5d45a0
fffff880`07905c40 00000000`00000004 : 00000000`00000000 fffff880`03163180 00000000`00004d78 0000000e`0000017c : 0xcccccccc`cccccccd
fffff880`07905c48 00000000`00000000 : fffff880`03163180 00000000`00004d78 0000000e`0000017c 00000003`00002f8c : 0x4
SYMBOL_STACK_INDEX:  0
SYMBOL_NAME:  atikmdag+267cad
FOLLOWUP_NAME:  MachineOwner
MODULE_NAME: atikmdag
IMAGE_NAME:  atikmdag.sys
DEBUG_FLR_IMAGE_TIMESTAMP:  4c21766c
STACK_COMMAND:  .cxr 0xfffff88007905220 ; kb
FAILURE_BUCKET_ID:  X64_0x7E_atikmdag+267cad
BUCKET_ID:  X64_0x7E_atikmdag+267cad
Followup: MachineOwner
	 
  
 
Hope this helps,
Captain