That sounds really familiar. I think my last Windows gaming rig may have been this exact board. Had it fitted with a 1.33Ghz Tbird and used the ISA slot for my scanner. (Until I ended up with a free Adaptec 2940, that is.) It'll run Windows 98, but it'll be sort of a bear to get going. (You'll need the chipset drivers from VIA/ABIT, and be *very careful* to install them in the right order.)
(Edit: Yeah, looked it up, that's it exactly. It's a good board... but I would recommend Windows XP for it. 98 was pain and a half. I mostly ran Windows 2000 on mine. Also, if yours has the "RAID" feature with the HPT370 chip I recommend *not* using it, either use the native IDE ports or use the HPT ports in just "plain disk" mode.)
I would probably pick this over the ABIT, only because the drivers for an Intel 815 will probably be easier to find and better written than the ones for the ABIT board.
You know, Trash, if you get *really* desperate I have a couple VIA C3 mini-ITX motherboards in (beat-up) micro cases. (They use a 12V wall wart for power.) I'm planning to set up one, coincidentally enough, to drive my new EPROM burner which requires *DOS*, but maybe I could part with one. I don't know if Windows 98 drivers for those exist, however.