Is your Zyxel 660 ADSL 2+ Modem/Router no wireless or Zyxel 660 HW with wireless
I take it as a HW as you say a USB adapter and you want to add second pc
I take it the present wireless system is working fine
Why do you want to remove the setting on the first pc???
Just buy a second USB adapter if laptop do not have a build in one and connect it the present wireless system by setting the SSID name and the security code