It is much easier to connect an old printer to a new computer than it is to connect an old computer to a new printer. Most modern printers come with a USB interface because it is faster and easier to configure than parallel interfaces used in years past. If your computer is less than 10 years old, chances are that your PC has a USB interface and plugging in a new printer will not be an issue. However, if you have an older PC, it probably does not have a USB port for which to plug in a USB printer. You will need a speciality parallel to USB port conversion adaptor to make the connection work.
Shut down and power off the computer to which you want to connect the USB printer.
Connect the parallel to USB port adaptor to the parallel port on the computer. Tighten the thumbscrews into the sockets to the left and right of the port.
Plug the AC adaptor for the port adaptor in an available electrical socket. If the device gets its power from the keyboard, disconnect the keyboard from the computer and insert the plug-in adaptor into the female socket of the "Y" cable provided with the parallel to USB port adaptor. Plug the male end of the port adaptor "Y" cable into the keyboard connector port on the computer.
Insert the flat end of the USB cable into the female slot on the parallel to USB port adaptor. Plug the other end of the cable into the printer.
Follow the manufacturer's directions for setting up the USB printer and installing software drivers and applications.
Some USB printers require that you install the software before connecting the printer cable. If this is the case, wait until prompted before plugging the cable into the printer. Unless your computer is really old, consider buying a USB port add-on card instead of a parallel to USB adaptor. The add-on cards are much less expensive than the adaptors.