Update: I have fully cleaned the PC and decided to stick to MS DOS completely.
The on-board SIS graphics chip is pretty horrible so I replaced it with the most logical & era-correct S3 Trio 64V+. Only 1MB for now but a card with 2MB is on its way so I can have 800x600 at 16 million colours in Windows 3.1.
The original mWave card has been replaced by the Sound Blaster 32 CT3670 which is an amazing card even though it lacks OPL3 (I can barely tell the difference anyway). I use Unisound by default since it uses so much less conventional memory.
The hard drive has been replaced by a compact flash adapter mounted to a PCI slot at the back which makes it easy to remove & add files manually this way.
I also replaced the floppy drive with a Gotek with LCD screen - it may be a temporary thing but it was handy to install DOS & Windows with.
The BIOS is limited but I'm surprised by its compatibility. I've tested a handful of "difficult" games so far including Innocent until Caught (always tricky to get sound working) and they all work great so far.
The only point of "worry" is the DVD drive - I need to find a Mitsumi quad speed to replace it with. It's too loud and no slow down utility seems to work. Well, that and the Pentium 120 CPU has its heatsink glued to it which is annoying if I wanted to replace it with a Pentium 166.
All in all, I'm surprised by the PC. For being 27 years old, everything still worked perfectly.
Retro game fanatic.
IBM PS1 386SX25 - 4MB
IBM Aptiva 486SX33 - 8MB - 2GB CF - SB16
IBM PC350 P233MMX - 64MB - 32GB SSD - AWE64 - Voodoo2
PIII600 - 320MB - 480GB SSD - SB Live! - GF4 Ti 4200
i5-2500k - 3GB - SB Audigy 2 - HD 4870