How do i change my sicurity network password

For that you need to reset your router to factory defaults.
Then reconfigure fix this problem.
First RESET your router to defaults.
for that press RESET button for 10 seconds RESET button is in back side of router.
Then connect your router to computer with ethernet cable.
Then you can access it with following link.
http://192.168.1.1
or
http://192.168.0.1
type user as "admin" and password as "admin" or blank or "password"
Then you can see configuration page of router.

Click on wireless security check wep code it is your password to connect internet .You can also change it there then save and restart router to take effect.
Let me know if you need further assistance.
Thanks.