Do you still see the Dell printer in your Control Panel Devices and Printer screen?
At the Start Menu type printer in to the search bar.
From the Control Panel section choose the Devices and Printers.
If you see the printer there, right mouse click and choose Remove Device.
I'm guessing this was a USB printer? Do you still have the printer?
Call up Device Manager with the printer plugged in.
At the Start Menu type device and Device Manager from the Control Panel section.
Look for Printers in the list and click on the little triangle. What printer is reported?
You can right click and choose Disable or Uninstall.