Multiple BSODs for the past 2 days

Hi, sorry for posting again. This is just a follow-up from my previous post:
http://www.sevenforums.com/crashes-debugging/102785-multiple-assorted-bsods-2-days.html

I ran memtest86+ (standard test) on my 2x2GB Team Elite DDR3 sticks. Testing each stick for 5 passes showed no errors. Later I'll be testing my other pair, 2x1GB GEIL DDR3. Since Ken mentioned that I should also test the slots, I'm thinking of testing the next 2 sticks on different slots, basically trying to hit 2 birds with one stone, testing both the stick and the slot at the same time.

I was wondering, If all the sticks have no errors and all slots are ok, is it safe to say that the problem might be software or driver related? Would doing a fresh install be a good solution to the problem?

Also, my mobo has an ATI chipset and I now have an nVidia GPU, will installing the ATI southbridge drivers conflict with the nVidia GPU drivers?

Thanks in advance!

ok, please go to your old post, I will post stuff there!