Hardware lockup - need suggestions for diagnosing

[Larry Cook]

Dan, Ben, Ric, and others that replied directly,

Thanks for your replies and suggestions.  Here's is what I've done and 
know so far:

Hard drive - I removed the hard drive and disabled it in the BIOS. 
Still have the problem.  (And yes Ben, I've already backed up the user 
data.  Thanks for asking.)

Disable things in BIOS - I disabled the few things that the BIOS lets me 
disable: power management, legacy usb, minipci, serial port, auto-wake, 
and a few other things I don't recall.  Still have the problem.

Memory DIMMs - I tried with only one DIMM and even tried a DIMM from 
another DELL Latitude laptop that has not had any problems.  Still have 
the problem.

Video - Dan suggested using a Live CD and just trying the console.  How 
do I do that?

External warming - Not sure how to do this other than light a fire in 
the fireplace, but that might tempt me to throw in the laptop! :-)

Reset connectors, etc. - Haven't tried this yet.

eBay - I did a quick check and found a dozen or more of this model, both 
fully working and partial systems.

Memtest86/86+ - (Ben, thanks for the links.)  This is last since this is 
what I spent most of my time on.  Both versions of memtest behaved the 
same.  When the system is stone cold (off over night), memtest does not 
finish writing it's initial text to the screen before it locks up. 
After it's been left sitting for 15-20 minutes I power off and then on 
and memtest finishes writing all the text, but the elapsed time never 
increments, although in some cases test #0 did update with a non-zero 
percent complete.  After it's been on a while longer and I power off and 
then on it eventually gets to test #5 [block move] and hangs.  This 
consistently happened if I let the tests run w/o intervention.  If I hit 
'c' and run tests #6, #7 and #8, they all pass.  I even let test #6 run 
for 32+ passes as the web page says is needed to hit all patterns.  The 
one interesting thing is that after running test #6, I hit 'c' and 
selected test #5 and that ran multiple passes w/o a problem.  But if I 
power off and on the computer hangs on test #5.  This was pretty repeatable.

Does any of this memtest behavior indicate any specific component?  Or 
do others have additional suggestions?

If I can't solve this, I'll be going the eBay route.

Thanks,
Larry