Using Win98 FE, sometimes I run it 5 hours without crashing, other
times (say after backing up to USB) it will crash repeatedly until
safe-mode twice in a row.
Check MSconfig, 1st or last tab, it should show full path/exe of
things that start at startup.  You can uncheck most of those and
re-start them daily within a 'startup.bat' batch file, which of
course should contain an antivirus and a firewall program ( in my
case AVG and look N Stop 2.x)  Soon to consider tds-3 anti-trojan
also...
I have win9x set to boot to a menu, I choose Dos Prompt.  There I
am able to deltree c:\temp before boot, and scandisk c: if there
was a crash.
It is also advisable to weekly run safe mode twice in a row as a
precaution.
I now every few days Cntl panel > Int options > del temp files AND
 local content, and run AVANT and FIREFOX vs having IE crash daily.
 ...and defrag every few days, (C: and i: , the latter where I have
 set the location of 'temp internet files').
INcidentally there is a registry cleaning program c*ahem*cleaner, that I
could not run UNLESS win9x was in safe mode w/o crashing, however
'check for issues' tab within it ran in just seconds that way vs.
20 min > crash if run the regular way.
If I have important stuff to do at a crash, it is easier to boot
Freebsd and do stuff w/in the two minutes that windows would take
to reload, I use BootIt to dual boot and to backup by image to
cd or file.  OTOH Freebsd is a learning curve, anyone should spend
at least 40 or so hours w/ setup, and check it's forum site beforehand
to check 'which version should I install'  etc.
BSD I boot 'disabled acpi' as compiles seem to complete more often that
way.  Maybe you can try that setting in Bios for Win9x if possible.

Jeff Bouquet