Please make sure the Operating System you are using corresponds with the printer driver.In other words,make sure the driver you're installing is compatible with the Operating System on your PC.
Check out your Operating System's compatible drivers for downloads from this Dell support site.
Make sure you unlock the scanner bed by pushing the scanner lock down.
Check the USB cable connections and make sure its secure.
If problem persists,return the product if still on warrant.
Hope this helps.Thanks!