Is it a 1500 or 1500n? Big difference
1:Is printer using DHCP (if 'n')? If so, there is the problem. The driver expects a static IP address, and if it changes, you need to reinstall the driver.
2: Clear the NVRAM. Don't recall exact procedure on the 1500 series, has to do with turning on printer an holding open the front door.
Sorry I don't remember more, stopped being the Dell Printer tech almost a year ago when they moved support to Canada.
Check on Dell.com, see what the procedures are for clearing nvram on that model.