I fixed the problem by swapping out the wifi card with one I have sitting around waiting for a battery to arrive. Thanks to all for the suggestions; I was mainly wanting feedback on whether it's likely, as I read elsewhere, that a wifi card would fail on a 2011 Macbook Pro. We have this happen very infrequently with ASUS Chromebooks and Lenovo laptops but I've never had one fail on a Macbook Pro. It is getting pretty old I guess. Trombonebuck, I am the IT department; at least the only one working on MAC stuff! I did verify the wifi was working before I tried swapping the wifi card! Thanks to all for the suggestions!
We mostly have phones and Windows laptops attached to the wifi around here and no one else expressed any problems; so I'm going to take my Macbook Pro over to check this out; it's a 2012 model but it should tell me if the wifi is up and down or not!