Inspiron 9200 BSoD plus more fun

OK. another fun one here. inspiron 9200 Media Center SP2. The dang thing just randomly blue screens with ipnat.sys errors. It has just recently started getting DEP errors and closing Windows Explorer. Attached are some sample dmp files along with the text from the BSOD. The DEP errors just started after the motherboard was replaced by Dell support because of a faulty power connection. Power issues are resolved and now we get DEP and BSoD. As always, thanks for any help you can provide

Blue Screen txt =
driver_irql_not_less_or_equal
0x000000d1 (0x00000004, 0x00000002, 0x00000001, 0xF4DEA3DB)
ipnat.sys address= F4DEA3DB base at F4DE3000, DateStamp 415b3714


AP

Inside the MiniDumps:

BugCheck 1000000A, {8, 2, 0, 804f8fd5}
Probably caused by : ntkrnlpa.exe
Probably caused by : ipnat.sys
Probably caused by : tosrfusb.sys (Bluetooth USB Miniport Driver)
Probably caused by : ipnat.sys
Probably caused by : ipnat.sys (provides a data store for Windows Firewall).

If you are using a third party firewall, go to :
Start -> Run -> Services.msc
And disable Windows Firewall

You may also need to update your drivers, especially the Bluetooth Driver
Go to Device Manager to do this

Thanks...It appears as though the driver updates have resolved a vast number of the blue screen issues. However, I still get DEP errors that close down Windows Explorer. Is it safe enough to just disable DEP? I have run a virus scan, root kit scan, windows updates...We are now running AVG Internet Security. I will look through the event viewer and see if there is any info associated with the DEP errors. Thanks again for your help