How to change WiFi settings of HP Laserjet P1102W?

In the install directory for the 1100 series there is an executable that takes you through the reconfiguration of the P1102w wireless settings. In Win 7 in (C:\Program Files\HP\HP LaserJet P1100 Series) The executable is (wificonfig.exe) Run this with the printer next to your laptop or desktop with the printer on and a USB cable available but not connected, and follow the instructions given by the program. This takes you through the wifi setup without the tedium of uninstalling and reinstalling anything.

You can save your router's config, change it to match your previous router, log into the http interface of the printer and change settings to new values from there. The printer will save them and become unavailable until you restore the settings you saved as per beginning of this message.