So you just think one of the contacts is dirty and obstructing the connection? I've looked at them, but it's in a tight spot, I might look again.
The thing is, when I put RAM in DIMM A, the computer will power up, the harddriver spins up initially, the backlight comes on, but about 5 seconds later the HDD sleeps, and nothing else happens. No error beep codes from the mainboard or anything, no flashing lights. There's no indication of a detectable error. I would think that the motherboard would be able to detect an error with the RAM and emit an appropriate sequence of error beeps. That's really what gets me. As soon as any memory is in DIMM A the machine simply doesn't do anything.
When I sent my computer in for repair, they upgraded my BIOS to a version that was JUST released a couple days AFTER I got my tablet back. ... Maybe I'm grabbing for straws. It's just the machine runs a lot slower with half the RAM, although I've dealt with it for a year, now.