R700P won’t work

> R700P won't work

   "R7000P"?  Look for "Model" on the product label.

> Model: PA7000P-100NAS|NETGEAR AC/DC Power Adapter 12V 3.5A

   Nothing to do with anything?

> The router won't even show as a device I can connect to.

   On some wireless device, or what?

> [...] I don't know how to fix it

   Did you consider trying this radical concept (which works for some
people):

      https://en.wikipedia.org/wiki/RTFM

   Visit http://netgear.com/support , put in your (actual) model number,
and look for Documentation.  Get the User Manual (at least).  Read.
Look for the LED descriptions and "Troubleshoot".  Pay particular
attention to the "WiFi On/Off button with LED".  Did you press it?
Further reading might not hurt, either.