My network is not showing up on my list of networks I have a Mac OSX.  My network is not showing up on my list of networks. I am able to get online on this computer but not on the other computers in the house connected wirelessly.  This has been the case today but was not this way before.
You will need to figure out if it is a logical or physical issue. Protocol incompatibility is a common cause of these failures, maybe the router reset and configured itself into an incompatible protocol ("802.11 n Only" for example). Sometimes the network connections utility itself is the problem, to discard this you can type airport -s in the "Terminal" app and see if there your network appears. If not, you can run a Wireless diagnostic with the OS tool, you can open it by holding the alt key while clicking the network icon at the top bar. 
The utility will guide you trough the steps and give the information that it can get about the problem. 

If with the previous steps things still don't work or show the cause of the problem, maybe it is at the router side. You will have to verify protocols and configurations according to your router/Acces point model, as every manufacturer has their own configuration. 

Apple has an article referring to this, you should check it out if haven't: Wi-Fi: How to troubleshoot Wi-Fi connectivity