Distorted or fuzzy screen - Mohaa - idle

Everytime I have played mohaa on windows 98 in the same windows session(ie not rebooted), use the computer for a little while, leave it and come back 1hr or so and move my mouse to switch the monitor back on the screen is distorted and frozen.

Windows is still active and I can still manage to guess where the start shutdown.

But by pressing <print screen> this makes a clear picture of the desktop and not distorted but still frozen ie not interactive.

Done the lot, update drivers etc…
Tried different monitors and cables, definitly a software fault.

Geforce 4 ti 4200 128mb
Windows 98se

IT ONLY HAPPENS when mohaa has been played I’m guessing it has something to do with the way opengl and windows talk to eachother after playing mohaa.

Thanks in advance for any help!