First trying disabling any security on the router and seeing if you can get online then. If so, then probably either you typed the passphrase in wrong or their is some sort of compatibility between the type of security your using and what your laptop can do. If you can't get online then, connect a ethernet from laptop to router and see if you can get online. If you can, could be a IP conflict, if you cant, your 655 may be in bridge mode or something and your PC is taking the IP. Try turning off the desktop, rebooting modem, and then rebooting the laptop and see if you can get online.