a] Either you cannot do some changes if you are administrator due to earlier credentials(username and password) was set by other person and he was not there anymore. Without it, you are going nowhere to do some amendments.
b]printer does not have valid non-zero IP address (which again,if you would like to change it(unless the credentials not been set) you would need to know of it before doing some changes.
1]Turn printer off
2]Press Go and Cancel button simultaneously for about 10 seconds while powering the printer back.
2]After you would see the Attention,Ready and Go lights finish cycling, the printer is now to a Ready state and the reset is complete.
What is the default ip address after it goes to factory default state?
I will have to recall on this. Will get back on this sooner. But as i still remember it was 160.x.x.x which i figured out after i run one .exe file from the CD printer drivers that HP provided. From there it able to scan the printer IP address when it was in Factory Default State.
P/s: This should applicable of all 2010 series printer