Are you looking for the wireless password or the password of the router?
If you want the password of the router, then try the default password of the router. If the default password doesn't work then you will need to reset the router and reconfigure the router.
If you are looking for the wireless network password, then you will need to open the set up page of the router. Is there any computer connected to the router ? If not then you will need to connect the computer to the router. Or any other computer which is able to go online using the router. Check the IP address on that computer. open the set up page of the router. Set up page of the router is the page where you will find all the settings of the router. under the wireless section you will find the wireless network password
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