Asrock should have revived one of their various 4core-DUAL motherboards
(DUAL VSTA, DUAL SATA2, Dual-880Pro, etc) instead of this dinosaur based
on the 865 chipset. The only component on the board that doesn't have
win-98 drivers is the 7.1 audio.
Those various DUAL motherboards have both AGP and PCIe slots and can
take both DDR and DDR2 memory. They are based on the VIA 880Pro chipset
which has win-98 drivers. I bought 6 of the DUAL-VSTA boards about 4
years ago (still have 4 of them new in-box) and it's a great board for
win-98.
Regarding the 775i65G motherboard - it sucks that it only takes DDR ram,
and I have my doubts about the SATA controller.
I have a Gigabyte socket-370 P-3 motherboard with i875 / ICH5r chipset
and unless Intel fixed this at some point, the SATA controller was very
unstable when used with Windows 98 (and possibly any NT-based OS).
Now try getting a socket-775 CPU these days, and DDR ram...