Blue screen CRITICAL_OBJECT_TERMINATION (f4)

Hello,

I am facing a problem that drives me crazy. There are two identical desktops Optiplex 3020 with Windows 7 64 Bit and there is a user that gets repeating blue screens.
CRITICAL_OBJECT_TERMINATION (f4)
A process or thread crucial to system operation has unexpectedly exited or been terminated.
Several processes and threads are necessary for the operation of the system; when they are terminated (for any reason), the system can no longer function.
Arguments:
Arg1: 0000000000000003, Process
Arg2: fffffa80052e1b30, Terminating object
Arg3: fffffa80052e1e10, Process image file name
Arg4: fffff80003388500, Explanatory message (ascii)
Debugging Details:
------------------

fffff880`06181e38 fffff800`03411142 : 00000000`000000f4 00000000`00000003 fffffa80`052e1b30 fffffa80`052e1e10 : nt!KeBugCheckExfffff880`06181e40 fffff800`033bc13b : ffffffff`ffffffff fffffa80`05b06060
fffffa80`052e1b30 fffffa80`052e1b30 : nt!PspCatchCriticalBreak+0x92fffff880`06181e80 fffff800`0333c894 : ffffffff`ffffffff 00000000`00000001 fffffa80`052e1b30 00000000`00000008 : nt! ?? ::NNGAKEGL::`string'+0x17486
fffff880`06181ed0 fffff800`03083113 : fffffa80`052e1b30 fffff800`c0000005 fffffa80`05b06060 00000000`00a70380 : nt!NtTerminateProcess+0xf4
fffff880`06181f50 fffff800`0307f6d0 : fffff800`030ceb0f fffff880`06182a38 fffff880`06182790 fffff880`06182ae0 : nt!KiSystemServiceCopyEnd+0x13
fffff880`061820e8 fffff800`030ceb0f : fffff880`06182a38 fffff880`06182790 fffff880`06182ae0 00000000`00a71e90 : nt!KiServiceLinkage
fffff880`061820f0 fffff800`03083502 : fffff880`06182a38 00000000`000120e4 fffff880`06182ae0 00000000`00a71968 : nt! ?? ::FNODOBFM::`string'+0x488e4
fffff880`06182900 fffff800`0308207a : 00000000`00000001 00000000`00a70a98 00000000`00000001 00000000`000120e4 : nt!KiExceptionDispatch+0xc2
fffff880`06182ae0 00000000`76d38e5d : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiPageFault+0x23a
00000000`00a70aa0 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : 0x76d38e5d

PROCESS_OBJECT: fffffa80052e1b30
IMAGE_NAME: csrss.exe
DEBUG_FLR_IMAGE_TIMESTAMP: 0
MODULE_NAME: csrss
FAULTING_MODULE: 0000000000000000
PROCESS_NAME: csrss.exe
EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - Die Anweisung in 0x%08lx verweist auf Speicher 0x%08lx. Der Vorgang %s konnte nicht im Speicher durchgef hrt werden.
BUGCHECK_STR: 0xF4_C0000005
CUSTOMER_CRASH_COUNT: 1
DEFAULT_BUCKET_ID: VISTA_DRIVER_FAULT
CURRENT_IRQL: 0
STACK_TEXT:
STACK_COMMAND: kb
FOLLOWUP_NAME: MachineOwner
FAILURE_BUCKET_ID: X64_0xF4_C0000005_IMAGE_csrss.exe
BUCKET_ID: X64_0xF4_C0000005_IMAGE_csrss.exe
The error occurs several times a day without any pattern that points to special reason. All hardware components have been changed from one place to the other but the error only occurs at the (right site) place. Therefore I think it must be a combination of user interaction and hardware. The newest drivers and all patches have been installed last month but the problem still exists.

Does anyone has an idea what the reason for the blue screens might be? Any help will be appreciated.