Tracy L: A "Reset" will indeed make your router operate the way it did when you purchased it and you will use the Default passwords to do the setup!
A "Reboot" will just restart the router and clear the CPU of any errors in the existing setup. Your current settings all stay in place. There are lots of people who do a reset when a reboot would work just fine for the problem.. To reboot, unplug the router for 30-60 seconds then reconnect the power. It will reboot and start up and that may clear your issue.
The latter. It's possible there will be no password on it after you reset i.e., it's wide open to anyone. Put a password on it after you reset, also change the admin credentials use to logon on the router config portal.
If you do a factory reset on your router you will have to reconnect using the default network name(SSID) and password.
Resetting as in unplugging it and plugging it back in will not change the password.