I can't help much from here, I'm afraid. If Windows detects a problem with a USB device, a balloon pops up and tells you to click the message to see more details. If, however, the USB port fails completely, Windows won't see a problem unless it shows in Device Manager.
Try another port and see what happens. The Belkin dongle should show a green light if it's active. Has it ever worked before and do you have another computer in which to test it?