BSOD - PFN_List_Corrupt, IRQL..., and now Memory_Management

I got home after being gone for a couple weeks turned my desktop on and started having issues with my internet connection. I was unable to complete any downloads, pages were slow to load, etc. I wasn't sure what the issue was, but figured wth, I'll just do a fresh install of windows. At that point the windows install was only about 2.5 months old.

Now after the fresh install I'm getting bsod restarts and am at a loss as to what is wrong. I'm in the process of doing all the windows updates, but I should still not have as many bsods as I'm having in the process of updating.

I've got a retail copy of Windows 7 x64 Ultimate. The install is now 2 days old and the hardware (mobo, cpu, memory, and bd-drive) are all 3 months old. One of my hard drives is probably 6 months old and the other is a couple years old. And my video cards is probably 5 years old or so(I know it's time for a new one. I'm hoping this isn't the issue as I can't really afford a decent one right now.)

Anyway, everything should be attached correctly. Thanks in advance for the help!
-Matt

I will update the vid card from your link and test my ram with memtest86+. I had run the windows memory diagnostic with 8 passes and it didn't find any issues that way. Will post results from memtest86+ after I run it.

As for antivirus, I don't feel it's necessary until I get the bsods figured out. Once that happens, I'll install av software.

I already have the latest drivers for my vid card. The beta release does not appear to be compatible with my card. Rebooting now to run memtest86+

I disabled verifier and ran memtest. The following is what I received (which if I'm reading correctly means the 2nd 4gb stick I have is bad):
Test:4
Pass:8
Failing Address: 001020c1d68 - 4128.7mb
Good: cd0a2e05
Bad: cd022e05
Err Bits: 00080000
Count: 1
Cached: 8138
RsvdMem: 2476k
MemMap:E820
Cache: on
Ecc: off
Test: std
Pass: 17
Errors: 825
Ecc Errs: 0

So...if I'm right I need to get my RAM rma'd to fix my problem.

Hadn't planned on returning it just yet. Figures there was more to test first. Will try the sticks separately and report back. Thank you

Well I've been running the pc for several days with the stick i thought was bad and haven't had any bsods. Guess it's time to switch it out for the other stick. Kinda looking like maybe an issue with the motherboard instead of the ram???