Try simly taking you CD or downloading the drivers from DELL.COM and reinstall the driver anew, don't connect the printer at first if it's a "setup.exe" installer, if it's a non setup.exe, connect printer and use the Add printer button, then the try the autodetect button.
Failing that go to device manager, right click My COmputer, Properties,, Hardware and then device manager.
click on it, press DELETE key, unplug USB lead
Reboot PC, reconnect printer and install
Good Luck . .