> Never tried USB before anywhere, and the empeg is my only USB device.

Without another USB device (like a Microsoft Intellimouse Explorer or something),
it will be hard to diagnose completely, but there's a couple things I haven't seen
mentioned in this thread yet:

1) If the USB plug on the system case is separate from the motherboard, it might
be a problem with the internal cabling. For example, the ribbon cable that connects
the port to the motherboard might be plugged in backwards. When I added the USB
ports to my case, the instructions that came with the cable were incorrect and told
me to plug in the cable the wrong way. Simply reversing the plug at the motherboard
fixed the problem. However, if your motherboard has the USB ports soldered directly
to it, then this doesn't count.

2) BIOS firmware. Some motherboards have flash BIOS upgrades available. It's
possible that there were bugs in your motherboard's USB support and you'll need
to download a new BIOS and install it. Check the website of your motherboard
manufacturer.

Good luck.