15-inch Mid-2010 memory upgrade issues

Question

Hi,
I have a 15-inch mid-2010 MBP running Mountain Lion, that I upgraded from 4 to 8 Gb of memory in Sept. 2012. The memory i purchased was a 2x4 gb set of Corsair Value rated at 1333 MHz. The upgrade went smooth, and i did not have any problems for a few months.
Then late in december or early in january, I had a few Kernel Panics. I didn't think too much of it, as I was busy with exams, and thought it might be a software issue or something, maybe related to VMware Fusion. The KP's started getting a bit more frequent, and suddenly one day the machine wouldn't boot at all, it just KP's at the Apple logo and then goes in a loop. I now suspected a memory problem, as my experience tells me that this is a usual cause of KP's.
I started fiddling with the memory sticks, and determined that one of the blocks would boot, so i went to the place i bought the set and talked to them. They agreed that the one block was probably faulty, and replaced my memory with a 2x4 Gb set of Corsair Mac Memory. This is 1066 MHz CL7, and should be compatible with MB,MBP and iMac, according to the packaging. The problem is that the machine will not boot with this memory either. It just goes for the same loop and KP's at the Apple logo. I can't even get this to boot with one stick in the machine, so it's arguably worse.
The machine works well with the original memory, It's been a rock solid main machine with 4Gb of ram for about a month now.
I tried PRAM and SMC reset to no avail. I tried booting into boot camp with the new memory, but it just never seems to load Windows. This also works with the old memory.
I'm a bit lost as to what i should try next. I suspect it's a problem with the Logic Board, i just don't see how, seeing as it used to work with 8 Gb, and that it still works with 4 Gb.
Any suggestions would be appreciated

Answer 1

So, i've played around with things a bit more. 4 gigs of ram is still rock solid. I've had the memory in a friends computer, an HP PC, where it works just fine.
Also, the computer starts up fine in fail safe mode if i hold down shift during boot, but that's no way to live.
I should probably have mentioned in my first post that I have replaced my optical drive with a 64 gb SSD that i boot OS X from. Since Windows does not start up either, and i've had that part of the setup for about two years, I wouldn't think that is the problem.
The computer has been running 15 passes of Rember this night, and was still running when i got up, so it's clearly not entirely broken.
Any suggestions?