need help cisco 7960 Ip phones any ideas?

[itman18]

Need help I'm working on 10 Cisco 7960 Ip phones (bought used) (all was used on the same network by a company that went out of business and they where all working when they disconnected them they where used with the no power supply option) 7 of them I was able to setup by entering the setting option and pressing the setting button but 3 of them when I press the setting button noting happens the phone is now plugged up with a power supply my problem is that the phone is trying to connect coming up on the screen Ethernet disconnected when I try plug it up to the internet it go's true the process but can't connect but at the whole time I can't get in to settings option when I press the settings button trying to get in to setting option nothing is happening (once I'm in the settings option I know how to set it up )(I already set up 7 of them that I've no problem) already tried a factory reset by holding the # button while start up and so on