We have seen instances where this specific Zebra thermal printer will not work with driver that is supplied with it.
If you search online for drivers for this printer model, you will probably be directed to UPS's site, and you can download and follow the instructions on UPS,com to install this printer.
If this still does not work, please delete the printer form your Windows machine and download and follow the directions for the Seagull Windows driver (link below), and this should work as per our users.
http://www.bartenderbarcodesoftware.com/drivers/printer-driver-features.aspx?m=Zebra+ZP+450+CTP
(Please report any issues to us, so we can address/update this article.)