Computer suddenly says there is no wireles adaptor?

Had the thing for three years w/o a problem. Installed a Motorola modem went to change the security settings and suddenly it cut out telling me there was no wireless. The connection box says "The settings saved on this computer for this network, do not match the requirements of the network" When I tried to hook up to the internet. I had to hook the computer up to the ethernet cable to get it to work. have had problems with the internet cutting in and out lately when it stopped working. I thought it was the router/modem which wouldn't work even with the cable, so I tried another one. Which is working so far. Do wireless adapters die out? Not sure whats up. Computer is an HP Pavilion desktop if that helps