Linksys Config Help

I need help i had a small network in my home i got 4 pc one is install at my room at the other 3 intall in my childers room . My child access many site that show some nude photo even crack ans serial. i try to disconnect the cable of wifi to our router but my son now how to connect it. i read some article that my linksys router can change the config so that my children can access Internet w/o my permission can anybody tell me how to change the config of my router. thnxz alot for the help