at the back of your router there iwll be a small hole or a button...mabye it will say reset: this is what you do :
1: PLUG YOUR ROTER IN
2: HOLD DOWN THE RESET BUTTON FOR 20 SECONDS
3:UNPLUG YOUR ROUTER
4: HOLD YOUR RESET BUTTON FOR 20 SECONDS
NOW U HAVE RESET YOUR ROUTER TO ITS ORIGINAL SETTINGs..THERE WILL BE NO WAP NUMBER ( you need to set a new one