Internet connects most of the time but not always
Ok, I seem to have a little problem with it. Sometimes when I turn it on it boots up fine, no chime but I have the sound muted. When I go to launch firefox (newest one) it never loads. My airport menu (thingy at the top of the menu bar) says I have a full signal (the airport express and iMac are less than 20 feet away from each other). Same thing with Safari. Everything else still works, i.e. xbox 360, MacBook, wii, and an iPod touch, at the same time. Sometimes it works right the first time but other times it will not work at all. Restarting and turning it off then back on doesn't help either. I have to turn it off for over 30 minutes then try again and it always works after that. Any ideas?
p.s.- sorry about the length