I want my Laptop use without Ethernet cable, since I have changed the Password I can`t

Hi
You don't mention the make/model of your router, so I must remain fairly general rather than being specific to your kit.
There is usually a "reset" button on most routers that resets them to the original factory settings, including the access username and password. It is often recessed so that a pencil, biro or some such instrument is required to press it. Doing this will wipe out all personal settings that you have saved to the router. The default value for these can usually be found printed on the router or in the manual, for which you may have to go the makers website.
Having done the reset you can then access the router and put your settings back in to make it work as it did. Having done this there is also an option somewhere that allows you to back up the settings to your PC - sounds a good idea !!
You need to make sure that the encryption settings on your router and PC/laptop are the same and that they are recognised by each other
Cheers