BSODs, and instant restart when plugging in headphones???

[AngusJS]

I built my own computer a few months ago, and have had a BSOD every few days for about 2 months.

==================================================
Dump File : 020511-14492-01.dmp
Crash Time : 2/5/2011 9:41:50 PM
Bug Check String : UNEXPECTED_KERNEL_MODE_TRAP
Bug Check Code : 0x0000007f
Parameter 1 : 00000000`00000008
Parameter 2 : 00000000`80050031
Parameter 3 : 00000000`000006f8
Parameter 4 : fffff800`030dad91
Caused By Driver : ntoskrnl.exe
Caused By Address : ntoskrnl.exe+70740
File Description : NT Kernel & System
Product Name : Microsoft® Windows® Operating System
Company : Microsoft Corporation
File Version : 6.1.7600.16617 (win7_gdr.100618-1621)
Processor : x64
Computer Name :
Full Path : C:\Windows\Minidump\020511-14492-01.dmp
Processors Count : 4
Major Version : 15
Minor Version : 7600
Dump File Size : 292,248
==================================================

The BSODs don't seem to be connected to anything in particular.

But what is really weird is how my computer will sometimes instantly restart when I plug in headphones or a USB device to my front I/O panel. Plugging in one set of headphones while the microphone jack from another set is a guaranteed restart, but my computer has also restarted from just one jack, and even from USB connectors.

And the odd thing is, the restarts happen the second the jack/USB comes into contact with the socket - before any data could possibly be transmitted or the computer could even begin to recognize a device - almost as if the problem is electrical in nature.

Avast anti-virus and malwarebytes find no problems with my computer at all. I've looked inside, and all the cables and connections appear to be in order. However, I can't see the front I/O panel from the inside, so something could be wrong there, and I'd never know it.

AMD Phenom II X4 965 3.4 ghz
4 gig of ram
Windows 7 64

Any idea as to what might be going on?

Thanks