Wireless network not working

Ever since we connected my laptop to our network, the wireless part of our network has stopped working. We have Verizon fios internet, and whatever router comes with it. One computer is connected to the router through a cable, and it never has any problems with the internet. Another computer is connected wirelessly using a Belkin network adaptor thing, which worked just fine until the laptop came along. The laptop uses a linksys network card.

When we first tried connecting the laptop to the network, it wouldnt work unless it connected before the other wireless computer. For a while they worked ok... The connection was a bit slower, but nothing too bad. But now, my desktop, the one thats connected wirelessly, has no internet, and half the time it cant even connect to the router. The laptop was doing the same exact thing until a few hours ago, when it finally connected to the internet, but its ridiculously slow, and the connection dies every now and then.

Ive tried everything to get my other wireless computer working - turning off the laptop, restarting the router, disabling/re enabling the network adapter, nothing works.

We had this same exact problem a while ago when we still used Comcast internet with a Linksys router - everything was fine until a laptop came into play.

Does anyone know why the laptops keep on screwing up the network? Or how to fix it? Im open to any suggestions.