Mr.E Solved! wrote:

Your troubleshooting and methodology is accurate and thorough, but you
do not mention if you tried these solutions... if they seem rudimentary,
it's not meant in any way other than, "verify that":

1) Your monitor is properly recognized by Windows as make:model, and
that it is being driven properly it terms of sync and refresh rates. Can
you try a a different monitor?

Yes, the monitor is properly recognized and works fine.

2) Can you get back to your last known-good position? Such as old card,
old boot sequence/partition(s).

Yes and no. The old card is (electrically) broken. The system worked quite
well with an old GeForce 4 Ti 200, which I had borrowed for testing. When I
plugged in the FX5500, the problems came up.

3) You mention you wiped the "whole partition" this is suspiciously
worded, since you can't wipe "partial partitions". Did you mean to say
you left other partitions untouched on your HDD during these procedures?
Or you instead wiped the "whole volume" clear of partitions...

Yes, I meant fully formatting the Windows partition, overwriting it with zero
bytes to make sure everything has gone. The other partitions remained
untouched for backup and Linux reasons.

4) Verify you have stable current all the way from your socket to your
eyeballs. The 5500FX has a very different electrical profile than the
GeForce3Ti 200. This might cause instability where none existed before.

How can I test this?

5) Ensure all nvidia secondary applications are disabled upon windows
starting, such as nwiz and the driver helper service and the control
panel extension. While you may want them enabled later, since they do do
useful things oftentimes, you might want to see if they are a problem.

I have tried starting without any Autostart apps by disabling them with
msconfig, yet this didn't solve the problem.

As a new effect: when I tried booting up Win98SE this morning (cold machine?),
it started up flawlessly and let me even switch resolution and the Direct3D
tests ran as well. However, after trying to install a game, Windows started
freezing while the installer was showing me the README file(!). And, after
having to reboot, the old effects occurred again (..."wrong settings" etc.).
Is this of any help?

Thanks in advance!