Issues after a complete hard drive wipe, and Windows XP install... Many features don't work fully, or at all.

You may need to install the original motherboard's chipset driver - see if you have any CD. After that do a full back-up ( a C: or system partition image is ideal). Install the latest version of motherboard's chipset driver and latest version video driver from the manufacturer website. Some drivers, like nvidia for video, require to fully uninstall the "old" driver before you install the new version.