[tlug] apparent hardware problem(s) -- but where?

[BALUTA Chris <baluta@example.com>]

  [ Apologies if this message is too long, but I'd like
    to give as much info. to help diagnose my problem. (My
    computer problem, that is.) ]

   Tluggers,
    
   I've got a dell dimension 2400 that I've been
having some problems with. Specifically, the system
will occasionally not boot, reboot automatically or
simply hang up.



   My question: Does anyone know or, at least, have some
good ideas, as to where my problem(s) is/are?


  
   Here's the situation:

 - I originally tried to install Fedora from a CD (one
   of those multi-boot CD's from a Linux magazine), and the
   process just seemed to hang. (This was tried on multiple
   occasions.)

 - I was, after two or three times, able to install unbuntu 9.09
   (jaunty jakalope, or something) from the same cd. But then the 
   system, while sometimes running fine, would hang

 - I then tried installing a ubuntu 7.xx version, and had the 
   same problems

 - Now getting somewhat desperate/wondering if I had a hardware
   problem, I re-installed xp that the system came with. The 
   installation went fine, but the same sorts of problems hit 
   me (blue screen, etc.)

 Assuming/guessing it might be a disk problem (and having lots
of points on my yodobashi card), I bought/received and installed a new
(500 gb) disk and was able to install ubuntu 9.09. Same problems.
(Locking up/ screen colors going goofy, looking like a photographic
negative, etc.).  For stretches, things seemed to work fine, though.

  Meanwhile, ubuntu lets me know "it's time to update to 9.10."
So I allow it to go through the 1 1/2 hour process, and things
seem ok. Great. No problems. Log out and let the machine
sit for a couple of hours. Log in. System locks up! Reboot attempt -- no
good (disk light is on, I can hear it chugging along, but a vast,
blank screen. I waited a good few minutes -- much longer than previous
boot ups took to complete -- to no avail.) Reboot attempt - good. 
Conclusion?  "Dig around online for ideas, then send off a request for 
help to tluggers."

    Some other notes:

  - memtest86 has been run throughout this process. On 2 or 3 occasions,
there were no errors. On the others, there were a plethora of errors.

  - The crashes do not appear repeatable. I've tried to run the same
software/click the same icons that I'd done on the previous lockups
and auto-reboots, but there have been no repeats. 

  - The crashes seem to occur when clicking on icons, beginning 
an x session (eg. session begins just fine, but clicking on icons/menus 
gets no response), clicking on menus, playing blackjack, etc. No problems 
with, eg. running vi or a shell script.

  - I had originally had an old (circa 2004) version of fedora running,
and had no problems. (Why no update? My landlord wouldn't allow
the work needed for internet access, so the machine became an occasionally
used toy).  New landlord this summer = internet ok. Upon running
firefox -- a 2004-ish version -- it crashed spectacularly while accessing
a video-intensive website. From that point on, firefox was gone -- a needed
file was now missing. I did not investigate how extensive any damage
was, figuring I was going to upgrade soon. But from that point, things got
wonky -- X sometimes didn't work: I'd log in, x would start to run,
and then...reboot. Or it would return me to the log in screen.

    I admit, this has been a bit of fun, learning things I should
have learned a while ago. But the point total on my yodobashi card
is running low now, so I'd like to be able to pinpoint the problem.

    Any & all help greatly appreciated!

          -Chris