64 bit - Diagnosing Blue Screen (IRQL_not_less_or_equal) Windows 7 64bit

I've searched high and low for an answer to this one. I recently removed my nVidia graphics card and the crashes are now less frequent. Here's the info from my latest mini dump. Can anybody shed any light on this?

Thanks!

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Dump File : 032413-14320-01.dmp
Crash Time : 24/03/2013 22:55:22
Bug Check String : IRQL_NOT_LESS_OR_EQUAL
Bug Check Code : 0x0000000a
Parameter 1 : fffffd8004695fe8
Parameter 2 : 0000000000000002
Parameter 3 : 0000000000000000

Parameter 4 : fffff800029669d5
Caused By Driver : ntoskrnl.exe
Caused By Address : ntoskrnl.exe+75c40
File Description : NT Kernel & System
Product Name : Microsoft® Windows® Operating System
Company : Microsoft Corporation
File Version : 6.1.7601.18044 (win7sp1_gdr.130104-1431)
Processor : x64
Crash Address : ntoskrnl.exe+75c40
Stack Address 1 :

Stack Address 2 :
Stack Address 3 :
Computer Name :
Full Path : C:\Windows\Minidump\032413-14320-01.dmp
Processors Count : 4
Major Version : 15
Minor Version : 7601