Wi Fi

I have a Dell Inspiron 1525 laptop. It will not connect wireless to my Belkin N150. It use to, then one day it quit. I have an HP laptop and it connects wireless  just fine. So I don't think it is the router. I have tried to reinstall the router. And the PC tells me there is a network available,  but it will not connect. My question is... Can the wifi card be bad? Is there a key combination that might have been put in by accident? Or any other reason for this problem?