the i-o actually has two usb ports. only the connector for one is installed.
how did you take xp off your i-o? did you reformat with the h.d. in another computer, or what? you probably have parts of xp still on the h.d.
another way is install the h.d. in another computer and delete the windows and program files directories as well as everything in the root directory. i copy the whole win98 directory from the windows c.d. into the hard drive, put the h.d. in the i-o and install from that.
did you install the VIA 4-in-1 drivers? the chipset driver should be the first thing installed after the o.s., the Trident display driver is next, followed by the usb driver. the VIA sound driver is fourth on a ver5 i-o. i put each driver in its own folder, uncompressed, before the h.d. goes into the i-o.
also, i never let windows install other programs into the program directory. each gets its own directory(folder). this makes changes easier, later.