Not sure what brand of wireless router you have but most have a system reset in the back where you stick in a pin to reset it to the factory settings, then you should be able to login without any password, this will completely reset the router so you'll need to setup security again if you had that setup before.
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Not sure what brand of wireless router you have but most have a system reset in the back where you stick in a pin to reset it to the factory settings, then you should be able to login without any password, this will completely reset the router so you'll need to setup security again if you had that setup before.