Here I'm trying to revive a Gigabyte GA-586S.
I've cleaned it, replaced the missing battery holder, put contact cleaner in the sockets and checked for bad solder joint and broken traces.
I've tried two different CPUs (P166/P166 MMX) and a variety of RAM sticks.
I managed to install DOS alright but it now completely freezes either immediately or a second or two into trying to run a program, sometimes it freezes even during going through the AUTOEXEC.BAT.
It's running the latest available BIOS.

Any idea what might be wrong or what I could try?

https://theretroweb.com/motherboards/s/gigabyte-ga-586s