Problem with wireless connection?

i got a links cisco wireless router and connected it to comcast cable about 2 weeks ago cuse i got rid of at&t...at first it was working will connected atomatically...now it signs in and signs out by itself on ps3...i also have a laptop connected to it but the laptop internet is perfect...i also dont have secuirity on my links router....why does my ps3 disconnect i got the ps3 in july 2009..what can be causes