so, when you open your network discovery window, no wireless options are available?
1. are you on a laptop? you might have switched or the wireless adapter. double check.
2. did you change and wireless settings such as make it undiscoverable? try manually inputing your wireless information.
3. if all else fails, reset your router (after double checking the above) and try to connect. (should be a reset button on back, but its small so get a paper clip and push and hold for 30 seconds)