Windows 7: Random BSODs by ntoskrnl.exe

Past two weeks i have been recieving random bsods mostly when i try to load up multiple windows or browser tabs or wen a game reaches a point where it has to load up textures or movies. I have had Bsods before due my audio drivers but not anymore. Past two weeks i have been recieving bsods in very close proximity. Need help. Its very frustrating. I thought updating windows will help but it has made no difference or worse i feel.

System is 5 years old i.e only the motherboard. Rest of the components have been upgraded couple of times in these five years. I have had no recent hardware additions.
All my drivers are upto date.

I have had total of 6 BSODS past two weeks of which all the dump files have been attached. The most recent one is

Dump File : 122511-23431-01.dmp
Crash Time : 12/25/2011 10:00:09 PM
Bug Check String :
Bug Check Code : 0x00000109
Parameter 1 : a3a039d8`95df59e1
Parameter 2 : b3b7465e`e85c2937
Parameter 3 : fffff800`03929820
Parameter 4 : 00000000`00000001
Caused By Driver : ntoskrnl.exe
Caused By Address : ntoskrnl.exe+7cc40
File Description : NT Kernel & System
Product Name : Microsoft® Windows® Operating System
Company : Microsoft Corporation
File Version : 6.1.7601.17640 (win7sp1_gdr.110622-1506)
Processor : x64
Computer Name :
Full Path : C:\Windows\Minidump\122511-23431-01.dmp
Processors Count : 4
Major Version : 15
Minor Version : 7601