Windows Vista SP1 Blue Screen Problems, Part Deux

I was way ahead of myself when I thought the "new" Vista SP1 from March 23rd didn't have any Blue Screen problems I had earlier with the SP1 from February. Here are some of the ones I've been getting. This first Blue Screen one was when Windows was coming up after a reboot, when SpeedFan (a utility I use to monitor system temperature) was loading:

page_fault_in_non_paged_area 0x00000050

I then upgraded SpeedFan to a newer version, 4.32 to 4.33. And then things seemed to run okay. But then I came home to another Blue Screen:

system_service_exception STOP 0x0000003B

dxgkrnl.sys

Oookay- I think that may have been trigger by a Media Center recording taking place because upon reboot it started to record a show in progress, but then I had error messages about Windows Update terminating and then the Media Center terminating.

I left the computer and then about a couple hours later I got the irq_not_less_or_equal Blue Screen. And I knew it was time to do a System Restore once again.... So no SP1 for me for now on this machine. If anyone with a similar hardware configuration is having a similar problem I'd like to hear about it. My machine is as follows:

-Windows Vista Premium 64bit
-Gigabyte GA-P35-DS3R with Q6600
-4 gigs of RAM (2 x 2 gigs)
-Nvidia 8600 card

The tough part is that the blue screens are of various variety and seemed random, so it's hard to pinpoint the cause. Under regular Vista non SP1 the system is rock solid.