I have an HP Officejet Pro L7580 network printer that’s connected (via a LAN cable) to a Netgear Wireless Router. Two computers are hardwired to the router with LAN cables, and I rarely have any trouble printing from them. The other two are laptops that connect wirelessly to the printer through the router. One of these laptops I rarely print from. On the other laptop, which is running Windows Vista, the printer keeps going Offline.

I narrowed the problem down to an IP address issue. IP (Internet Protocol) addresses are used to specify the location of each computer on the network. My router has its own IP address and it assigns a separate address to each computer and to the printer. You can check your printer’s IP address by doing the following:

  1. Open the Windows Control Panel.
  2. Click the option to view your Printers.
  3. Right-click the printer’s icon and click Properties.
  4. Click the Ports tab. (Above the Ports list near the bottom of the window, you might have to drag the little line that separates the Port column from the Description column to view the port numbers.)

If you’re having trouble with your printer going offline on this computer, then Windows might be using the wrong port number for your printer. Go to one of the computers from which you can print and check the port number that Windows is using for the printer. Jot it down. (Even if Windows is using the correct port number on the computer from which you cannot print, creating a new port as I show you in this article, can still solve the problem.)

Now, return to the computer on which the printer is appearing as Offline and create a new IP port using that address. Here are the steps:

  1. Open the Windows Control Panel.
  2. Click the option to view your Printers.
  3. Right-click the printer’s icon and click Properties.
  4. Click the Ports tab.
  5. Click Add Port.
  6. Click the option Standard TCP/IP Port and then click New Port…
  7. Follow the onscreen instructions to create the new port with the printer’s correct IP address – the one you jotted down earlier.

Tip: Robin, the online tech support person at HP who was so helpful in troubleshooting and fixing my problem, gave me an excellent tip. Open your Web browser. In the address bar at the top, instead of typing a web page address, type the IP address for your printer and press Enter. (If you get a security warning, click the option to proceed to the site.) I’m not sure this works with all network printers, but on my HP network printer, it displays a cool control panel for the printer.