How come I cant get online with my PS3?

I never had any problems before. Now when I try to sign in it says A connection to the network could not be established go to settings-network settings and check your settings. But all of my settings are fine I never had this problem before what's going on?How come I cant get online with my PS3?
CHECK OUT MY BA ITS EXCATLY THE SAME PROBLEM EXCEPT U 2 NAMED IT DIFFERENT EITHER WAY BOTH METHODS WORK FOR WHAT I SAID MY METHOD WORKS FOR 3 SIGNED OUT ERRORS

http://answers.yahoo.com/question/index;鈥?/a>

IF THAT DOESNT WORK EMAIL MEHow come I cant get online with my PS3?
just wait a while this has happened to me before usually happens with a wireless system a small technical problem but after a while you can go online
Reset your router if using wifi or if using cord connection reset modem.
Oh my did I have this problem a lot. Turns out I had a crappy router. It was a D-Link N router and I basically had to get a new router since the whole router sucked. Also you may have the PS3 far from the router and be receiving bad connection. Try resetting your router or just wait it off. That's if you're lucky. BTW my router worked fine for several months then it just gave up.