First of all, if printing doesn’t work, check the print queue. If you see NT_STATUS_ACCESS_DENIED, remove the printer and add it again, but when it asks you to authenticate, try entering:

Username: guest
Password: guest

If you have an HP LaserJet 4P– like me– then make sure you choose the “HP LaserJet 4 series - Gimp-Print v5.0.0-beta2″ Printer Model option. This is because this printer only supports PCL.

Do not select the “HP LaserJet 4 Plus”. This is a PostScript driver. I made this mistake the first time, and my printer spat out tons of gibberish.

Once I fixed these 2 things, printing worked perfectly. Hope this helps!