Have just replaced old monitor with new basic CRT and get message "A fatal exception 0D has occurred at 16CF:000014E3. The current application will be terminated" when try to boot to Windows 98. It won't even boot to safe mode and the monitor supplier's tech support tells me that this means it isn't a video driver problem. So the fact that it's a new monitor could be a complete red herring.
Suspecting that reinstall of Windows would help, I have tried to boot from the Hewlett Packard system restore disk which came with the machine, but the thing keeps trying to boot from the HD.
Apart from the new monitor the only other thing that's changed recently is that a couple of weeks before the old monitor went down I installed AVG anti-virus, that appeared to be working OK but maybe it is causing the problem.
I have tried booting in 'step by step' mode, with initialisation commands echoing to the screen. The last command seen before it fails is something like msmouse.vxd.
I am completely stuck now, so all suggestions welcome!