Welcome! My suggestions would be to investigate the black blob on the CPU card near the capacitor C6.
If you can verify the CPU speed, and clean (very corroded) the speed jumpers at J16 and make sure they match the CPU speed (typically 233MHz). Remove the red block (bump on the end...
OpenEmu is great for consoles and arcade roms, but not specifically OS9. I have always liked SheepShaver, although sometimes getting the settings correct is a bit tricky.
This was my first year, so I was just scoping it out to see what I could possibly do for a display/sale. Next year, possibly a van or trailer to haul stuff out there. 6 hour drive for me.
Perler bead projects
The Back to the Future time device.
And I got a 16 bay 2.5 server from the free pile. No drives, missing mobo, but the backplane for the SAS drives will go into one of my cheesegraters.
I never liked the AGP tabs... if you have a screw on the io plate, it should stay in place fine without the tab.
Some motherboards have what looked like a clip that went around the entire AGP slot. I am not sure if that is even removable (likely some tabs at the lower edge of the connector)...
I stopped by Free Geek Minneapolis again today, and dug through the scrap again... well I found another PrairieTek 240 (with the metal cover vs clear)!
This one has the Molex power cable and wires tagged. 5V line was broken off, but I can solder that back on.
Controller board seems to have...