Whether motherboard or stick, the RAM was probably a big part of the problem...memory problems can do some very strange things to operating systems. Don't use DIMM3...Put larger capacity sticks in the other two sockets. I use Corsair memory almost exclusively and have never had a failure. It's spendy, yes, but is worth it in my opinion.
I'll see if I can get Johanna to help you get your files back into your possesion...she's pretty good at that.
Glad you are back up and running!