Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I presume the printer was configured to print through a wireless connection.
If so, the change of modem involves a change of parameters that causes the former install of the driver to become invalid in some ways, disconnecting it or making it incapable in the new situation.
The simplest and easiest way to cure this is, to uninstall the printer from the printer's list (select it there and use the - button to remove it) then restart the computer, then install the printer anew. The parameters will now be valid for the current network situation, and the printer will work again.
If you need information as to the details of the uninstall-restart-reinstall I have just outlined, just Reply letting me know.
(If this answers your question, please rate my answer. Thanks.)