Hey Bear, nice to see you
I have had a look at the MSI site and they recommend getting the USB 2.0 drivers for XP from Windows Update as they are certified etc...
The USB ports on the front of the case probably go via a long(ish) cable to a "header" on your motherboard. Have you been inside the case recently and possibly dis-lodged them?
Saying that, it sounds like a Windows issue. Try deleting all the USB components from the "Device Manager" and then re-boot. When you are prompted for the driver just use the new one from M$.
Good luck.