k ty guys for ur reply.
out of everything you guys said the only thing I havent try is changing channel which I will try to do and see what happens.
the wireless is secure and they get kick off from the router until they reset the cable modem then it comes back online again but it happen again they get kick off form the router but the cable modem never goes off.

no porn lol it happen doing anything or nothing .
my thing is I have verizon dsl and they supply me with their own wireless router/dsl modem and I have dsl for about 2 years and this thing is rock solid it never ever goes down and is pretty fast at all time. when I had cable modem I was warn not to use a router for whatever reason.

I have my wireless router next to my monitor and my cordless phone and also a speaker and I even dectect a bunch of wireless conection from my neighboors so I know for sure interference has nothing to do with this problem.
I will install the latest firmware for their router and maybe that can help also.