Here's the cause of the recent reboot caused by the above image in Firefox.  I have no idea what win32k.sys is.. but it looks like a function call to GreSetLayout() caused the crash.  Sounds like a graphics related API call?
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*                                                                             *
*                        Bugcheck Analysis                                    *
*                                                                             *
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KERNEL_MODE_EXCEPTION_NOT_HANDLED_M (1000008e)
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: c0000005, The exception code that was not handled
Arg2: bf8243e0, The address that the exception occurred at
Arg3: b6ee3608, Trap Frame
Arg4: 00000000
Debugging Details:
------------------
EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".
FAULTING_IP: 
win32k!GreSetLayout+2f
bf8243e0 56               push    esi
TRAP_FRAME:  b6ee3608 -- (.trap ffffffffb6ee3608)
ErrCode = 00000002
eax=00ffffff ebx=b6ee36d0 ecx=b6ee36d0 edx=00000000 esi=e353de00 edi=e2dafcdc
eip=bf8243e0 esp=b6ee367c ebp=b6ee368c iopl=0         nv up ei pl zr na po nc
cs=0008  ss=0010  ds=0023  es=0023  fs=0030  gs=0000             efl=00010246
win32k!GreSetLayout+0x2f:
bf8243e0 56               push    esi
Resetting default scope
CUSTOMER_CRASH_COUNT:  1
DEFAULT_BUCKET_ID:  DRIVER_FAULT
BUGCHECK_STR:  0x8E
LAST_CONTROL_TRANSFER:  from bf830d74 to bf8243e0
STACK_TEXT:  
b6ee368c bf830d74 e353ddf8 e2dafcd4 00000002 win32k!GreSetLayout+0x2f
b6ee36f0 bf85fe5f 52010f74 00000004 0518dff8 win32k!NtUserBuildHwndList+0x131
b6ee3874 bf86039b 52010f74 00000000 00000028 win32k!xxxTooltipWndProc+0x198
b6ee38ec 8053c808 52010f74 00000000 00000028 win32k!AnimateFade+0xb3
b6ee3934 7c90eb94 badb0d00 0012ef0c 88c941a0 nt!ObpPushStackInfo+0x75
WARNING: Frame IP not in any known module. Following frames may be wrong.
b6ee3940 88c941a0 00000018 b6ee3c7c 00000000 0x7c90eb94
b6ee3944 00000000 b6ee3c7c 00000000 0012fcbc 0x88c941a0
STACK_COMMAND:  .bugcheck ; kb
FOLLOWUP_IP: 
win32k!GreSetLayout+2f
bf8243e0 56               push    esi
FAULTING_SOURCE_CODE:  
SYMBOL_STACK_INDEX:  0
FOLLOWUP_NAME:  MachineOwner
SYMBOL_NAME:  win32k!GreSetLayout+2f
MODULE_NAME:  win32k
IMAGE_NAME:  win32k.sys
DEBUG_FLR_IMAGE_TIMESTAMP:  43446a58
FAILURE_BUCKET_ID:  0x8E_win32k!GreSetLayout+2f
BUCKET_ID:  0x8E_win32k!GreSetLayout+2f
Followup: MachineOwner
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