USB Root Hub Problem

All of a sudden my USB hub stopped working. I am getting a yellow ! by my USB Root Hub in Device Manager. When I click on USB Root Hub I get this message: NTKERN.VXD device loader(s) for this device could not load the device driver. (Code 2). I tried every thing that was suggested by the Troubleshooting Universal Serial Bus (USB) Devices documentation furnished by Dell.
I've done the following:
1. Reinstalled driver.
2. Forced USB to be redetected.
2. Ran usbreg.exe for Win 98.
Nothing has worked. As I said before, the devices in which I had connected to the USB hub were working then they just stopped and I started getting the yellow!
My machine is a Dimension L600cx with 2 USB port connections. I had a Visioneer One Touch 5800 scanner on one side and a Kensington Optical Pro mouse on the other. Neither port works now. I really don't know what to do next.
Any suggestions would be appreciated.
Thanks,
Mike