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Both the dumps related to the drivers of your video card.
Click on the Start 
► Control Panel ► Programs ► Uninstall a program ► Uninstall everything related to; ATI and restart the system. Delete remnants of its drivers/older drivers using Driver Fusion/Sweeper.
Install latest drivers from: AMD Driver Autodetect
One of them come with bugcheck 124, which is a hardware bugcheck. Go throught Stop 0x124 - what it means and what to try step by step and see if it helps resolving the issue.
Code:
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************
Use !analyze -v to get detailed debugging information.
BugCheck 124, {0, fffffa800997a028, be000000, 800400}
*** WARNING: Unable to verify timestamp for atikmdag.sys
*** ERROR: Module load completed but symbols could not be loaded for atikmdag.sys
Probably caused by : GenuineIntel
Followup: MachineOwner
---------
0: kd> !analyze -v
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************
WHEA_UNCORRECTABLE_ERROR (124)
A fatal hardware error has occurred. Parameter 1 identifies the type of error
source that reported the error. Parameter 2 holds the address of the
WHEA_ERROR_RECORD structure that describes the error conditon.
Arguments:
Arg1: 0000000000000000, Machine Check Exception
Arg2: fffffa800997a028, Address of the WHEA_ERROR_RECORD structure.
Arg3: 00000000be000000, High order 32-bits of the MCi_STATUS value.
Arg4: 0000000000800400, Low order 32-bits of the MCi_STATUS value.
Debugging Details:
------------------
BUGCHECK_STR: 0x124_GenuineIntel
CUSTOMER_CRASH_COUNT: 1
DEFAULT_BUCKET_ID: WIN7_DRIVER_FAULT
PROCESS_NAME: System
CURRENT_IRQL: f
STACK_TEXT:
fffff800`00ba8a98 fffff800`03413a3b : 00000000`00000124 00000000`00000000 fffffa80`0997a028 00000000`be000000 : nt!KeBugCheckEx
fffff800`00ba8aa0 fffff800`02fa5b13 : 00000000`00000001 fffffa80`09748880 00000000`00000000 fffffa80`097488d0 : hal!HalBugCheckSystem+0x1e3
fffff800`00ba8ae0 fffff800`03413700 : 00000000`00000728 fffffa80`09748880 fffff800`00ba8e70 fffff800`00ba8e00 : nt!WheaReportHwError+0x263
fffff800`00ba8b40 fffff800`03413052 : fffffa80`09748880 fffff800`00ba8e70 fffffa80`09748880 00000000`00000000 : hal!HalpMcaReportError+0x4c
fffff800`00ba8c90 fffff800`03412f0d : 00000000`00000004 00000000`00000001 fffff800`00ba8ef0 00000000`00000000 : hal!HalpMceHandler+0x9e
fffff800`00ba8cd0 fffff800`03406e88 : fffff880`0958e000 00000000`00000001 00000000`00000000 00000000`00000000 : hal!HalpMceHandlerWithRendezvous+0x55
fffff800`00ba8d00 fffff800`02e968ac : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : hal!HalHandleMcheck+0x40
fffff800`00ba8d30 fffff800`02e96713 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KxMcheckAbort+0x6c
fffff800`00ba8e70 fffff880`084e4544 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiMcheckAbort+0x153
fffff880`04062d20 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : atikmdag+0x71544
STACK_COMMAND: kb
FOLLOWUP_NAME: MachineOwner
MODULE_NAME: GenuineIntel
IMAGE_NAME: GenuineIntel
DEBUG_FLR_IMAGE_TIMESTAMP: 0
FAILURE_BUCKET_ID: X64_0x124_GenuineIntel_PROCESSOR_MAE
BUCKET_ID: X64_0x124_GenuineIntel_PROCESSOR_MAE
Followup: MachineOwner
---------
0: kd> !errrec fffffa800997a028
===============================================================================
Common Platform Error Record @ fffffa800997a028
-------------------------------------------------------------------------------
Record Id : 01cdcadc89bcfb63
Severity : Fatal (1)
Length : 928
Creator : Microsoft
Notify Type : Machine Check Exception
Timestamp : 11/25/2012 7:16:23 (UTC)
Flags : 0x00000000
===============================================================================
Section 0 : Processor Generic
-------------------------------------------------------------------------------
Descriptor @ fffffa800997a0a8
Section @ fffffa800997a180
Offset : 344
Length : 192
Flags : 0x00000001 Primary
Severity : Fatal
Proc. Type : x86/x64
Instr. Set : x64
Error Type : Micro-Architectural Error
Flags : 0x00
CPU Version : 0x00000000000206a7
Processor ID : 0x0000000000000000
===============================================================================
Section 1 : x86/x64 Processor Specific
-------------------------------------------------------------------------------
Descriptor @ fffffa800997a0f0
Section @ fffffa800997a240
Offset : 536
Length : 128
Flags : 0x00000000
Severity : Fatal
Local APIC Id : 0x0000000000000000
CPU Id : a7 06 02 00 00 08 10 00 - bf e3 9a 1f ff fb eb bf
00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00
Proc. Info 0 @ fffffa800997a240
===============================================================================
Section 2 : x86/x64 MCA
-------------------------------------------------------------------------------
Descriptor @ fffffa800997a138
Section @ fffffa800997a2c0
Offset : 664
Length : 264
Flags : 0x00000000
Severity : Fatal
Error : Internal timer (Proc 0 Bank 3)
Status : 0xbe00000000800400
Address : 0x00003880084e4544
Misc. : 0x000000000003ffff
0: kd> !sysinfo cpuspeed
CPUID: "Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz"
MaxSpeed: 3300
CurrentSpeed: 3310
------------------
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************
Use !analyze -v to get detailed debugging information.
BugCheck A, {ffffffffffffffff, 2, 0, fffff80002e86556}
*** WARNING: Unable to verify timestamp for atikmdag.sys
*** ERROR: Module load completed but symbols could not be loaded for atikmdag.sys
Probably caused by : atikmdag.sys ( atikmdag+210c1 )
Followup: MachineOwner
---------
1: kd> !analyze -v
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************
IRQL_NOT_LESS_OR_EQUAL (a)
An attempt was made to access a pageable (or completely invalid) address at an
interrupt request level (IRQL) that is too high. This is usually
caused by drivers using improper addresses.
If a kernel debugger is available get the stack backtrace.
Arguments:
Arg1: ffffffffffffffff, memory referenced
Arg2: 0000000000000002, IRQL
Arg3: 0000000000000000, bitfield :
bit 0 : value 0 = read operation, 1 = write operation
bit 3 : value 0 = not an execute operation, 1 = execute operation (only on chips which support this level of status)
Arg4: fffff80002e86556, address which referenced memory
Debugging Details:
------------------
READ_ADDRESS: GetPointerFromAddress: unable to read from fffff800030b1100
GetUlongFromAddress: unable to read from fffff800030b11c0
ffffffffffffffff
CURRENT_IRQL: 2
FAULTING_IP:
nt!KeSetEvent+16
fffff800`02e86556 f6037f test byte ptr [rbx],7Fh
CUSTOMER_CRASH_COUNT: 1
DEFAULT_BUCKET_ID: WIN7_DRIVER_FAULT
BUGCHECK_STR: 0xA
PROCESS_NAME: System
TAG_NOT_DEFINED_c000000f: FFFFF88003322FB0
TRAP_FRAME: fffff88003322940 -- (.trap 0xfffff88003322940)
NOTE: The trap frame does not contain all registers.
Some register values may be zeroed or incorrect.
rax=fffffa8009a76000 rbx=0000000000000000 rcx=0000000000000001
rdx=0000000000000000 rsi=0000000000000000 rdi=0000000000000000
rip=fffff80002e86556 rsp=fffff88003322ad0 rbp=fffff88003322b80
r8=0000000000000000 r9=fffff88003322c90 r10=fffffa800a48c170
r11=fffff88003322cf8 r12=0000000000000000 r13=0000000000000000
r14=0000000000000000 r15=0000000000000000
iopl=0 nv up ei ng nz na pe nc
nt!KeSetEvent+0x16:
fffff800`02e86556 f6037f test byte ptr [rbx],7Fh ds:00000000`00000000=??
Resetting default scope
LAST_CONTROL_TRANSFER: from fffff80002e81569 to fffff80002e81fc0
STACK_TEXT:
fffff880`033227f8 fffff800`02e81569 : 00000000`0000000a ffffffff`ffffffff 00000000`00000002 00000000`00000000 : nt!KeBugCheckEx
fffff880`03322800 fffff800`02e801e0 : 00000000`00000001 00000000`00000000 407ac1ec`17431f6b ffffffff`ffffffff : nt!KiBugCheckDispatch+0x69
fffff880`03322940 fffff800`02e86556 : fffffa80`0e596c90 fffff880`073a1f1e fffff880`040639c8 fffffa80`0a4984a8 : nt!KiPageFault+0x260
fffff880`03322ad0 fffff880`076910c1 : 00000000`00000005 fffffa80`00000000 00000000`00000000 fffff880`080fc1cf : nt!KeSetEvent+0x16
fffff880`03322b40 00000000`00000005 : fffffa80`00000000 00000000`00000000 fffff880`080fc1cf fffffa80`0a497210 : atikmdag+0x210c1
fffff880`03322b48 fffffa80`00000000 : 00000000`00000000 fffff880`080fc1cf fffffa80`0a497210 fffff880`040639c8 : 0x5
fffff880`03322b50 00000000`00000000 : fffff880`080fc1cf fffffa80`0a497210 fffff880`040639c8 00000000`00000000 : 0xfffffa80`00000000
STACK_COMMAND: kb
FOLLOWUP_IP:
atikmdag+210c1
fffff880`076910c1 ?? ???
SYMBOL_STACK_INDEX: 4
SYMBOL_NAME: atikmdag+210c1
FOLLOWUP_NAME: MachineOwner
MODULE_NAME: atikmdag
IMAGE_NAME: atikmdag.sys
DEBUG_FLR_IMAGE_TIMESTAMP: 50650821
FAILURE_BUCKET_ID: X64_0xA_atikmdag+210c1
BUCKET_ID: X64_0xA_atikmdag+210c1
Followup: MachineOwner
---------
1: kd> lmvm atikmdag
start end module name
fffff880`07670000 fffff880`080f9000 atikmdag T (no symbols)
Loaded symbol image file: atikmdag.sys
Image path: \SystemRoot\system32\DRIVERS\atikmdag.sys
Image name: atikmdag.sys
Timestamp: Fri Sep 28 08:14:57 2012 (50650821)
CheckSum: 00A3EAAC
ImageSize: 00A89000
Translations: 0000.04b0 0000.04e4 0409.04b0 0409.04e4
Good luck.
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