The BSOD Mystery Solved?

The computer that is used the most in our home started to randomly BSOD (blue screen of death) about a couple of weeks ago.  It was a Phenom 9850 with 8 gig of DDR2 and Windows 7 Pro.  I think the random crashing started to happen after a Windows update was applied.  I thought it was some video card driver or a memory error.  Suspecting the video driver, I downloaded new drivers from AMD, but that didn't help.

Today, I thought maybe the Gigabyte mainboard was flaky so I swapped it with an identical one I had with another computer running Vista Ultimate Edition 32 bit (but with a Phenom 9650 CPU and 4 gig of Kingston DDR2).

When I popped the RAM from the Phenom 9850 box to swap into the Phenom 9650, I noticed that it was 2 sticks of Corsair, 1 stick of Crucial and 1 stick of GB Micro!  Hmm....  After swapping the hard drive for the two boxes, Windows 7 wouldn't boot.  I reset the BIOS and it still wouldn't boot.  I just left the 2 Corsair sticks in there and removed the two non-matching sticks and it would POST to the BIOS. If this didn't work, I would have checked the RAM with Memtest 86+ (I was pretty sure I checked the RAM for errors previously).  I had verified that the two sticks of Kingston were good with Memtest 86+ because I had bought them used from Kijiji a few weeks ago.

Then I thought I would take the 2 sticks of Kingston in the Vista box and put it into the Windows 7 Pro box.  That way I would have 2 sticks of Corsair (800 MHz) and 2 sticks of Kingston (667 MHz) in dual channel mode (8 gig total).  I put the Crucial and GB Micro sticks in the Vista box, but as single channel.  As I type this post, the Win7 Pro computer is not BSODing.  The Vista Ultimate computer is also working.

I had to activate both computers over the phone as the processor swap caused my Windows to 'deactivate'.  On the Windows 7 Pro machine, I had to reactivate Office 2010 (over the internet).  I suspect I will have to activate Office 2007 on the Vista Ultimate computer too.

Problem solved?  I hope so.  But, I've already ordered a Haswell Core i5 4430 CPU and Asus Mainboard from NCIX.  I'll be using 16 gig of DDR3 I bought last year when RAM was dirt cheap ($30 for 8 gig!).  So, about $550 later, I'll have a significant upgrade!  I haven't been using Intel CPUs at home for a long time because I was too cheap and settled for AMD instead.  This should be a significant performance boost!