Welcome to the AndroidForums, LibbyLu
Sorry to hear that about your N4
I'm pretty sure the phone should still be working, even if the screen is not.
Have you tried connecting your USB cable between the phone and a PC and seeing if you can access / view the files on the SD card?
That would be a pretty quick and easy way to tell if things behind the scenes are up and working, even if the screen is not.
Now that's not 100% reliable, but should give you the warm and fuzzies you are looking for
Also, try calling the phone and see if it rings...that will test a few more components and tell you that a few other things are probably okay.
Best of luck and let us know how things go!