Athlon II (or other Socket AM3 cpu) to test?

[Kolya Matteo]

Hello all,
My computer currently won't boot, and I think the problem is either
the cpu or the motherboard.  Unfortunately, I can't tell which.  I'm
wondering if anyone has an Athlon II, Phenom II, or Sempron which I
could borrow; or if anyone has a known-working system with a Socket
AM3 motherboard, in which I could try my cpu.

In the former case, I could pick it up and return your CPU, or you can
drop by my apartment and I'll test while you wait.  In the latter
case, I could come by to test my CPU in your system anytime that's
convenient.  I get around by MBTA, so I'd prefer not to carry my whole
desktop somewhere to plug a CPU in, but that's an option if nothing
else works.

I should point out that it is possible to have a CPU that kills
motherboards or vice versa, but since my machine was working fine,
then froze in use, then never booted again, and there weren't any
electrically traumatic events, I don't think that's the case here.

Feel free to reply off-list.  I'd also appreciate any suggestions of
alternate methods to diagnose the CPU vs. motherboard problem.

Details: The computer (Athlon II X3 450 in a Gigabyte MA770T-UD3
motherboard) was working fine, running Debian.  It ran overnight with
no problems; I was actively using it (selecting packages in aptitude)
when it froze.  I left it, probably an hour, with no change; no
response to keyboard (including leds), no response over the network.
I finally turned it off.  Ever since then, turning it on spins up the
fans, lights the power led, but nothing is on the screen; and I can
tell Debian doesn't boot "blind" because the keyboard doesn't light
up.  It doesn't seem to POST (unfortunately, there's no speaker in the
case or on the motherboard.)  I removed all non-essential hardware,
with no effect.  I tried a different power supply, with no effect.  I
tried each of the two sticks of ram individually, and moved them
around, with no effect.  I consider it unlikely that both sticks
failed simultaneously with no apparent cause (it passed memtest86+
previously.)

Thanks for any help.

Kolya Matteo