So fustrated! Cannot connect to the internet

My macbook is unable to connect to my belkin router wirelessly while my other computers are able to just fine. It gives me an error of saying incorrect password, then self-assigned IP. I even reformatted my macbook and it is still giving me this error. Any help would be appreciated. Thank you.

Well first up can you connect via an ethernet cable?

yes, I am able to connect through the ethernet wire, just not wirelessly.

With the cable attached, go into the browser administration page, select wireless, then set up WPA2 Personal with at least a 13 letter/number password.

What do you mean by browser admin page? the config page for the belkin router? thanks for responding btw.

Yes the browser configuration p[age is the same. Hook up by cable, go to the page and then to thew wireless section.

yes! it worked. Thank you very much.