Internet crashing every time games or movies are played.

What do you mean by "crashing"? Do you mean the internet stops working, or are you getting some kind of error message?

What kind of wireless modem do you have?

It's a Linksys E3000......It just crashes, no error message......Just connection is lost.....

Need more info. You can lose your internet connections in many ways, and exactly how your losing can tell you something about why your losing it. For instant, does it only effect wireless computers or wired too? On the wireless computers, when you lose the internet, if you look on the bottom right for the wireless icons, does it still say your connected?

Also, do any lights change on the router or the modem? And what kind of modem do you have? The Linksys E3000 is a router.

If the router itself is rebooting, as in turning off then back on, by itself, then it's likly a issue with the router and might want to contact Linksys to see if its under warranty.

The computers never seem to lose the internet, just the XBox's upstairs and the televisions. The laptops seem to be fine.

Sorry - the modem is a Scientific Atlantic 2100.

Hmm, that could be alot of things then, but I can't think of any that would be caused by Cox. Where did you buy the router and who set up the different devices? Do you have any experience troubleshooting network issues? This article may be helpful.

Thank you, I really appreciate your help. I'll try those ideas and see if anything helps. Thanks again!!!

So, I bought a booster for the upstairs and now the XBox's seem to be working perfectly. That being said, now my iPhone only connects to the internet when it feels like it. I'm about to lose my mind. haha

A wireless repeater for a Xbox? Thats going to half your wireless speed and cause alot of lag in games usually. Do you have a big house? What made you decide to get a repeater?

My husband came home with it. Not a good idea?

Well I wouldn't call it a bad idea, since it fixed one of your problems, I just wouldn't call it an optimal solution. If the reason the wireless wasn't making it upstairs to the Xbox was because your house is just naturally bigger then the routers broadcasting range, then thats one thing. But if the problem is some kind of active interference causing the Xbox to not be able to "listen" or connect to the network, then a wireless repeater may make it strong enough to overcome the interference, but your also adding fuel to the fire.  Smallnetbuilder has a good article breaking down the different ways to extend your wireless coverage, and the Pro/Cons of each.