how do I change password for my C3700 router?

Netgear has set up a community forum specifically for the Cable Modem products. Most of the people who watch that forum are more likely to have experience with Cable modems and know how to work it better than those of us who follow this router forum. Might be more likely to find someone who has a solution if the question is posted there:
https://community.netgear.com/t5/Cable-Modems-Routers/bd-p/home-cable-modems-routers

 

Wire connect a PC to the router and factory reset the router using the back push pin button. Hold it in for 10 seconds then let go, then log in to routerlogin.com or 192.168.1.1 (maybe 192.168.0.1) using a web browser and walk thru the setup wizard. This time write down all important information for safe keeping later on.

Please use this link to the main forum product list to review and choose where to make your posts. 
https://community.netgear.com/t5/NETGEAR-Forum/ct-p/en-netgear

Thank you.

How do I change my NETGEAR router password or network name (SSID)? | Answer | NETGEAR Support