well here is what id normally do:
1.uninstall the wireless adaptor drivers going to control panel>add remove programs and uninstalling them. Then i would reinstall and reset the pc.
2.reset the router , by holding down the button on the back of it for 30 seconds (note this will take any security and settings off it)
3.open the wireless config utility in the bottom right you should now detect your router click connect.
4.go start to setup security on the router again by going to internet explorer and typing 192.168.0.1 or 192.168.1.1 into the address bar