It could really be anything connected to the motherboard, but it's more likely to be the motherboard itself unfortunately. With RAM issues, you generally tend to see a lot of completely random error codes with these stop errors, and the logs themselves commonly indicate memory corruption. RAM problems generally cause complete havoc. Also, you have some very good quality memory there (Kingston). To this date, I've never found a user who has experienced issues with Kingston.

However, I think it might be a good idea to reseat everything initially just to be sure these connections have not become corroded. You'll be surprised how easy working with PC hardware is to be honest. It's all down to the odd screw or clip holding these components in place, and everything slides out. All plugs can only fit in one place, so it's hard to get these things confused.

First of all, open up the PC. There is normally just a few screws holding the side panel on depending on what PC you have of course. Remove the graphics card - again, just a screw holding it in place, and you'll then be able to lift the card out. Put the card back in again, and do that same for any other expansion cards. With memory, it's a similar process, but two white clips either side of the two chips which slide apart. When you insert the memory again, push down softly, and you'll see the two clips click back into place.

Physical motherboard problems can be impossible to detect, but the only visible signs of failure will be with the capacitors. Look for signs of leakage on the top of the capacitor, or on the side. Look for capacitors which appear fat or bloated as opposed to a perfect cylinder shape.

If there's anything your not sure of, let me know, I'll see if I can get hold of some video's and pictures.