Presario 5365/Win98SE - inexplicable shutdowns to a blinking cursor

I'm helping a friend with his Compaq Presario 5365 running Win98SE on AMD
K6-3D Cpu (400MHZ I think). Mobo manufacturer unknown with SIS 530 chipset.

Friend reports PC was acting sluggish and sometimes locking up. Says it
possibly began after a Windows Update was cancelled in the middle of
download.

At the same time he syas Norton Anti-Virus 2003 Pro was acting funky, as
NAV would not lauch from the system tray.

So I uninstalled NAV 2003 with the intent on re-installing (and updating
NAV via LiveUpdate).

However following the NAV uninstall I observed PC shuts down at random
times, usually after after 10-30 minutes after starting windows. The PC
functions just fine until inexplicable shutdown. (PC shuts down no matter
which apps are running, or if on internet or not).

When it shutsdown I just see blackscreen with blinking cursor in upper left
corner.

I installed Zone Alarm Internet Security Suite 6.x and also Adaware SE and
attempted to scan system but PC shutsdown in the middle of the scannning
with either.

Installed HijackThis but no unusual tasks running.

I ensured no bad BHOs were installed In IE.

I connected fine to internet and using IE6 ran Windows Update and installed
the latest critical updates for IE6 and Win98. And revisiting WindowsUpdate
shows all critical updates installed.

I disabled screensaver, wall paper themes and power management.

Ran System File Checker (SFC) in Safe Mode.
SFC reported the following files may be corrupted:
C:\windows\system\setupx.dll
C:\windows\system\fpwpp.dll

(used defualt search settings - searched
C:\windows\system
C:\windows\system32
C:\Program Files\Accessories
C:\Program Files\Common Files

for files with following extnesions:
386 / com /dll /drv / exe / mpd / ocx /scr / sys / vxd


System has MS Office 2000 installed. But FrontPage appears to not be
installed. So uncertain source of fpwpp.dll listed above.

I double checked all the tasks which were running and all related to
hardware installed on machine (I removed unneccessary tasks/services).
Still shuts down.

I cannot test ompact items showing up in tasklist related to HP LJ1000
printer, as friend did not bring printer with (I'm avoiding uninstalling
for this reason).

In MSCONFIG I chose Selective Startup and unchecked everything so they
would not load at Windows startup. PC still shutsdown unexpectedly.

I've allowed the system to sit idle in SafeMode to see if unexpectedly
shutsdown there as well. But it does not.

Right now before I post this I have regular Windows launched, with
selective startup chosen. Only items in task list is explorer, cpqeadm
(compaq keybd utility), bttnserv (compaq easy buttons utility), em_exec
(logitech), and systray. No HP printer or scanner drivers loaded.

I have had on for a half hour and no crash! So maybe it is an issue related
to the LaserJst drivers?

Will see if PC is crashed in the morning.

But to continue I have mixed thoughts on if it is a Windows issue or
hardware issue.

Bootlog.txt shows following four errors:

LoadFailed = C:\ESSOLO.sys
(which i think are real mode sound drivers... not needed... sound works
fine in Windows)

LoadFailed = ndis2sup.vxd
(not sure why this is but PC conencts to the intternet via dial-up fine and
PC is not conencted to a LAN)

INITCOMPLETEFAILED = SIS530V
(I assume this is for the SIS chipset with integrated video' video seems to
be fine in windows)

INITCOMPLETEFAILED = SDVXD
(not sure yet what this is)

No bad entries appear in Device Manager (no question marks) and all
hardware appears to be working correctly.

I ran scandisk from DOS prompt and some lost clusters were found and were
auto fixed. And then also ran full surface scan and a bad sector or two was
found which scandisk flagged.

Opening case I checked to be sure power supply and cpu fans were working
and areas around CPU was clear. Components don't seem to get overly warm.

Discovered the original 64MB RAM in PC (PC-100), was upgraded with two
additional 256MB PC-133 SDRAM mods. But Windows only reports 444MB (whereas
576MB=256+256+64 total was installed). I assume the system board just does
not support more than 444MB? Anywya I awapped in and out different combos
of RAM modules, and re-ordering mods in sockets with no positive results.

The Compaq BIOS Setup is quite lean (the fewest settings I have observed).
Does not provide any settings to alter memory timings, etc.

My friend states that the RAM was upgraded almost a year ago so and was not
having issues until recently.

I tested the ATX PowerSupply with an Antec PS tester and shows OK.

As a FYI...

My friend pulled the orginal hard drive from system in favor of a new
larger 80GB 9image of original hard drive was copied over a year ago or so,
same time as RAM upgrade). So I assume any hidden partion mirror recovery
files on the orginal hard drive are no longer available.

But found new hard drive has hidden system.sav directory which appears to
be the Windows recovery files (friend states he did not get a recovery CD
with PC, but I am not sure, As I assumed Compaq was delivering OEM WIn98 CD
with PC's back then).

Also I see C:\bootdisk which contains files to create a recovery bootdisk.

I'm sure I'm forgetting to include the many other diags I've performed.

Any thoughts on how to proceed troubleshooting this?

Should I proceed with a Windows repair from CD (I have Win98SE boot floppy
also)? If so which specific steps are recommended? Run Setup from the hard
drive hoping the PC will not crash?

Woody