Hi there,

I'm writing this because I'm out of ideas on the following, maybe someone can help...

So I have this board out of an old system:
https://theretroweb.com/motherboards/s/asus-p5vdc-mx

I wanted to sell it for cheap but lately had the idea if it would be possible to make it into a nice little and not too overpowered Windows98 + XP (dual boot) AGP system.
I have some components to choose from (CPU, RAM, video cards), so the goal was to NOT buy anything new for this "project".
So far so good.

The setup is:
- board: P5VDC-MX
- CPU: Celeron D 360
- RAM: 512MB DDR2 (2GB planned later on)
- video: on-board graphics for now (S3 something), later on either a Radeon 9600 / Ti4200 / FX5200 / FX5700
- harddisk: Samsung SSD 840 120GB (connected to onboard SATA)
- PSU: Fortron Source ATX-350PNF
- LPT & serial ports deactivated in BIOS

I've booted the system from floppy and then started Win98SE setup (files copied to the SSD beforehand).
The installation went OK and I could boot into desktop, even install the onboard video driver and select a higher video mode.
I'm not so sure anymore when exactly things got odd but nothing seems to work anymore.
After the next reboot the system reverted back to standard VGA mode telling there's some problem with the video adapter.
Another deinstall/install round later nothing changed. The system would generally freeze randomly, DirectX setup stopped after extracting the files into a temp folder without any message.
I tried to install the Via 4in1 drivers in several 5.xx versions, but the install routine would always say the setup was stopped and no changes were made to the system. Reason unknown.

Device manager was looking clean so far (besides the then not yet installed audio, LAN drivers).
But after some reboots there was an exclamation mark at the dual PCI SATA controller.
Removing this device in fail-safe mode lead to complete unability to boot in normal mode since driver reinstallation always fails with a freeze at the click on "next" after chosing the driver (Windows always offers the same and I can't seem to find any Via specific one as the 4in1 drivers don't seem to have the usual inf-files for selection).

Other uncommon things I've noted are strange looking (at least to me) autoexec.bat and config.sys files right after the initial Win98SE install process (files added to post), VERY slow transfer speed via USB (~some kB/s, didn't change with NUSB 3.x package), random system hangs for some seconds, random complete freezes, SSD performance ~500MB/s read and ~50MB/s write (as tested with ATTO), no drivers installing correctly, blue screens at boot, system hangs with blinking cursor at boot. List not exhaustive.

Sorry if this all sounds a bit chaotic but I can't remember any specific "event" that made it like that (it rather was like that right from the beginning), so I tried to list anything that I can remember.

Things I've tried so far:
- changed RAM
- installed R. Loew's Patchmem (shouldn't be necessary with 512MB as to my understanding but should harm either) & PatchSATA
- switched SATA mode in BIOS from normal to Raid (and back)
- toggled ACPI settings in BIOS
- reinstalled Win98SE with "/p i" parameter (read somewhere this would prevent Win98 from using ACPI !?!?)
- connected SSD to IDE port via SATA-to-PATA converter
- reinstalled Win98SE with SSD on PATA-port
- deactivated SATA ports in BIOS completely
- changed "PnP OS" in BIOS from yes to no and back

All in all this didn't help anything.
Things I haven't tried yet is using old IDE spinning rust instead of the SSD and installing WinXP only to see if there may be anything hardware related.

Is this some ressource conflict thing, some missing/wrong driver or a complete incompatibility between this board and Win98?
I suspect some SATA thing behind this but not sure how to circumvent.
I haven't had any similar problems installing Win98SE on other platforms in the past, but none of them was as modern as this.
What am I missing?