Not sure about Dell printers but most laser printers either jam paper under the toner cartridge out the back on where the paper comes out.
Also have you tried pulling the paper tray out and looking into the gap that teh tray goes in. Sometimes paper gets stuck in the feeder and stays there unseen.
oops seems I messed up with the stars and the reply -thank you so much for your advice -I tried the first thing you suggested and there was a barely visible string of paper caught on something -i just unhooked it and voila!!