You can perform a factory reset by holding down the configuration button (1st button on preview row) and button number 8 on the program row at the same time and then applying power or pressing reset.

WARNING: This cannot be undone, if you only want to temporarily set the IP address back to factory default, refer to the "I Do Not Know The IP Address Or Want To Reset It" article.  This process will PERMANENTLY reset all settings back to factory default.  Be sure you have notes on this configuration before performing a factory reset if you will need them later.