Dell USB ports don't work

I have a Dell XPS 400.

The device manager thinks that all the USB ports are working fine. However, if i pug anything in it is not recognized.

We tried to roll back the usb port drivers and it said that they have never been backed up.

We tried to update the drivers and it said there was nothing better available.

I have 5 ports in the back and if you plug anything into them then it locks the system up. The two in the front just gives an error message.

a couple possible different things might be at play so try:

Reinstalling drivers
You don't need rollback but re-install the drivers already there.
In device manager under USB you should see 4 different controller entries
=> For each one, Rt click to the controller and choose Uninstall (no worries driver files themselves are on your computer)
=> After ALL 4 have been uninstalled, from top menu items click Action -> Scan for hardware changes
=> The drivers will be reinstalled. When done try again

Power reset
If above doesn't help unplug all the power cables. This means unplugging the monitor cable as well as computer power cable. Wait about 15 minutes. Then plug back in and try again

Just as a point of interest USB devices are uually the first hardware device to go on failing hardware

I would suggest you confirm the USB is not working in Safe Mode either
To get to Safe Mode, repeatively press F8 key before Windows startup

You may need to run a Dell iagnostics Hardware test on all your hardware (I have not confirmed if your Model provides such a disk, but you should be able to chech here: All Dell Drivers, and Downloads fo Your System (http://www.techspot.com/vb/topic100658.html)