Run memtest for as long as you can. 5 hours at least. I think there is something wrong with you RAM module(s). Especially because you said XP and here on 7.
Code:
Microsoft (R) Windows Debugger Version 6.11.0001.404 X86
Copyright (c) Microsoft Corporation. All rights reserved.
Loading Dump File [E:\Temp\Rar$DI12.937\110309-25412-01.dmp]
Mini Kernel Dump File: Only registers and stack trace are available
Symbol search path is: SRV*C:\SymCache*http://msdl.microsoft.com/download/symbols
Executable search path is:
Windows 7 Kernel Version 7600 MP (4 procs) Free x64
Product: WinNt, suite: TerminalServer SingleUserTS
Built by: 7600.16385.amd64fre.win7_rtm.090713-1255
Machine Name:
Kernel base = 0xfffff800`02a09000 PsLoadedModuleList = 0xfffff800`02c46e50
Debug session time: Tue Nov 3 19:45:34.850 2009 (GMT-5)
System Uptime: 0 days 0:44:15.927
Loading Kernel Symbols
...............................................................
................................................................
...............
Loading User Symbols
Loading unloaded module list
..........
*******************************************************************************
* *
* Bugcheck Analysis *
* *
*******************************************************************************
Use !analyze -v to get detailed debugging information.
BugCheck A, {fffff6800037f550, 0, 0, fffff80002a4f2a7}
Probably caused by : memory_corruption ( nt!MiDeleteAddressesInWorkingSet+11b )
Followup: MachineOwner
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3: 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: fffff6800037f550, memory referenced
Arg2: 0000000000000000, 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: fffff80002a4f2a7, address which referenced memory
Debugging Details:
------------------
READ_ADDRESS: GetPointerFromAddress: unable to read from fffff80002cb10e0
fffff6800037f550
CURRENT_IRQL: 0
FAULTING_IP:
nt!MiDeleteAddressesInWorkingSet+11b
fffff800`02a4f2a7 488b1e mov rbx,qword ptr [rsi]
CUSTOMER_CRASH_COUNT: 1
DEFAULT_BUCKET_ID: VISTA_DRIVER_FAULT
BUGCHECK_STR: 0xA
PROCESS_NAME: firefox.exe
TRAP_FRAME: fffff88003911ed0 -- (.trap 0xfffff88003911ed0)
NOTE: The trap frame does not contain all registers.
Some register values may be zeroed or incorrect.
rax=0000098000000000 rbx=0000000000000000 rcx=0000000000006f08
rdx=0000000000000000 rsi=0000000000000000 rdi=0000000000000000
rip=fffff80002a4f2a7 rsp=fffff88003912060 rbp=fffff7000108c008
r8=fffffa8004212d78 r9=0000000000000001 r10=0000000000000a67
r11=fffff70001080000 r12=0000000000000000 r13=0000000000000000
r14=0000000000000000 r15=0000000000000000
iopl=0 nv up ei ng nz na po cy
nt!MiDeleteAddressesInWorkingSet+0x11b:
fffff800`02a4f2a7 488b1e mov rbx,qword ptr [rsi] ds:163b:00000000`00000000=????????????????
Resetting default scope
LAST_CONTROL_TRANSFER: from fffff80002a7a469 to fffff80002a7af00
STACK_TEXT:
fffff880`03911d88 fffff800`02a7a469 : 00000000`0000000a fffff680`0037f550 00000000`00000000 00000000`00000000 : nt!KeBugCheckEx
fffff880`03911d90 fffff800`02a790e0 : 00000000`00000000 0000000f`ffffffff 00000000`00001000 fffff800`02badbfe : nt!KiBugCheckDispatch+0x69
fffff880`03911ed0 fffff800`02a4f2a7 : 00000003`00000000 f6f00000`8c550867 fffff700`0108c000 fffff680`000043b8 : nt!KiPageFault+0x260
fffff880`03912060 fffff800`02a4deee : fffffa80`042129e0 fffffa80`00000000 fffff880`00000a67 fffff800`00000000 : nt!MiDeleteAddressesInWorkingSet+0x11b
fffff880`03912910 fffff800`02d5d7af : fffff8a0`0abcea50 fffff880`03912c20 00000000`00000000 fffffa80`041cc060 : nt!MmCleanProcessAddressSpace+0x96
fffff880`03912960 fffff800`02d37b3d : 00000000`00000001 00000000`00000001 00000000`7efd5000 fffffa80`06dbcb60 : nt!PspExitThread+0x47f
fffff880`03912a30 fffff800`02a57a43 : 00000000`03912ca0 fffffa80`069847e0 00000000`0293e710 fffff880`03912be0 : nt!PsExitSpecialApc+0x1d
fffff880`03912a60 fffff800`02a57e80 : 00000000`02b8fdb4 fffff880`03912ae0 fffff800`02d38710 00000000`00000001 : nt!KiDeliverApc+0x2eb
fffff880`03912ae0 fffff800`02a7a1f7 : fffffa80`041cc060 00000000`7efd5000 fffff880`000000c0 00000000`7efd5000 : nt!KiInitiateUserApc+0x70
fffff880`03912c20 00000000`00000000 : 00000000`00000000 00000000`00000000 00000000`00000000 00000000`00000000 : nt!KiSystemServiceExit+0x9c
STACK_COMMAND: kb
FOLLOWUP_IP:
nt!MiDeleteAddressesInWorkingSet+11b
fffff800`02a4f2a7 488b1e mov rbx,qword ptr [rsi]
SYMBOL_STACK_INDEX: 3
SYMBOL_NAME: nt!MiDeleteAddressesInWorkingSet+11b
FOLLOWUP_NAME: MachineOwner
MODULE_NAME: nt
DEBUG_FLR_IMAGE_TIMESTAMP: 4a5bc600
IMAGE_NAME: memory_corruption
FAILURE_BUCKET_ID: X64_0xA_nt!MiDeleteAddressesInWorkingSet+11b
BUCKET_ID: X64_0xA_nt!MiDeleteAddressesInWorkingSet+11b
Followup: MachineOwner
---------
Also, update your bios to latest available and run under "optimized default settings" from within it.
Check the event viewer logs for anything suspicious or related.
Update all drivers possible, for the system.
Disable Windows Search service as a test. Use services.msc at start menu search box.