As with any other printer or electronic device, problems with the HP Officejet 4500's hardware or software will cause the printer to not function as it should. When you experience a problem with the Officejet 4500's operation, you first must determine the cause of the problem before you can properly solve it. Problems with the printer software on the computer, the computer itself or the USB cable that connects the printer to the computer will also affect the printer's performance.
Check both ends of the power cord and the printer's USB cable to make sure they are securely plugged in. Plug the power cord directly into a power outlet instead of a surge protector or backup battery. Plug the USB cable into the computer and not a USB hub or other device.
Check the Officejet 4500's power light to see if it is illuminated solidly or is blinking. Wait for the light to stop blinking if you installed a new print cartridge in the previous 12 minutes, giving the printer time to initialize the new cartridge.
Unplug the power cord, open the printer's covers and remove the paper from the input and output trays if the power light continues to blink. Pull out any stuck pieces of paper from the inside of the printer and gently slide the cartridge carriage to the left and right sides of the printer, removing any debris that obstructs its movement.
Use the software application you used to send the print request to make sure the Officejet 4500 is set as the default printer. Click the "File" menu at the top of the window, then click "Print" and make sure the Officejet 4500 is selected in the pull-down menu at the top of the print window. Select the printer from the menu if it is not the default, then click the "Print" button to try printing again.
Right-click the small printer icon on the right side of the task bar, then see if a check mark appears next to "Pause Printing." Click "Pause Printing" if you see a check mark, resuming the pending print jobs. Close any other applications that are open on the printer to eliminate potential conflicts.