Hmm... it'd be nice if you'd post the full specs of your system.

VGA card problem maybe?

Try swapping/reseating RAM sticks.

I will do - I left the computer at my workshop. I'll bring it home tomorrow, so I can take some pictures and take an inventory of all the parts. I bought the mobo on eBay a couple of months ago. Basic machine with DOS 6.22 - was fun to put together!

Could it be a stability issue? Maybe try BIOS defaults or even reducing timings to slowest to see if it gets more stable.

I played with many BIOS settings - even put 'defaults' back in. I messed with the timings in the BIOS. I've changed video cards, I'd put different RAM in (even a single 8 MB stick). When I run basic DOS apps, all is well - no crashing it seems. I've made sure the computer is not on turbo mode too. I do not recall DOS ever crashing much at all back when these machines were current - it was pretty rare (based on my memory from a long time ago!) I've even disabled the external cache too.

Just remember that this DOS subforum is for DOS games on *modern* systems.

Rekon your on the right track.
Strip the PC back to basics. Video, Ram, HDD, that's it
Boot into dos bypassing config.sys/autoexec.bat

See if Doom runs now, and then slowly start building the PC up from that point.

Could you try Heretic shareware and see if that runs?

Yep, what chinny22 said.
Try to disable the Sound in Setup.
Remove Sound Blaster card completely.
Remove the Mouse.

Try using Doom+ Executable, and see if it works. https://sourceforge.net/projects/prboom-plus/ … .2.zip/download
Maybe its a compatiblity issue.

Do other Games also have this Problems ? try Descent.

Have you tested your memory subsystem ? run memtest86 2.0

Switch off "Turbo Switch Function" in the BIOS, if it exists. This cured a similar problem with Doom for me, in an Opti 495XLC board.

There's a Microsoft support notice about it causing hangs with some versions of Windows 9x, which gave me the clue. You'll lose the use of the turbo switch, though.

Sorry for extremely late reply everyone. I found the problem after all. The motherboard settings (jumpers) were incorrect. I am using a Intel DX4-100 overdrive chip, the settings were for another CPU. The table on how the jumpers should be set was a little misleading in terms of the way it was organized. Good lesson for me! Thankfully, nothing bad happened to the CPU. DOOM runs perfectly - no crashes. Thanks to everyone whom made suggestions.

Nice to hear! Now post a thread with specs, pics, and info on how you built it 😁