My Dimension XPS T700r worked fine until a week ago. For no reason, my USB Epson printer, USB netcam and my modem locked up.

The printer works fine with the parallel port, no luck on the netcam and the modem is back.

I have the dreaded yellow "!" in device manager on the USB Root Hub. I have done all the fixes including the file download, sfc replace and manually deleting the USB key with regedit.

What is NTKERN.VXD? It does not show up anywhere except in the device manager which has no details. I have reloaded Vmm32.VXD with no luck.