I just got a Mac (used) computer and hooked it up to my modem and router. Everything was working fine until I installed a new wireless printer (HP Envy 4520). The wifi is now only working through the printer. Other devices in the house show a wifi signal but it's not working. When I run a diagnostics test it says wifi does not have any problems. I'm assuming what has happened is it's locked into just the DNS for the printer because the network wasn't set up correctly to have multiple devices. I know this is a simple fix for someone who understands networking (but that is not me). Any suggestions?