Where can I get a replacement Startup DVD for the printer?
I do not know but i have connected it through Fast Ethernet with a fixed address... 192.168.2.2 ( on a Mac 10.9.5)
this is how it works with me:
go to the menu on top of the printer - go to connectivity
USB: in the USB part it should say Yes- Yes - the there should be no problem when connecting it tot the computer
Ethernet :In the ethernet part configuration give it the address 192.168.2.2-
connect the ethernet wire to the mac ( mac pro second port)
go to the mac;
I assume you have the drivers installed otherwise got to http://www8.hp.com/us/en/support.html and install the drivers
go to the system preferences/ network
give the ethernet 2 the number 192.168.2.1 - close
go to system preferences - printers
add a new printer
i should see by now the z3100
add the printer- ready