Slow or intermittent wireless/then disconnected

thats not enough info. it could be a dead router, too much interface, incorrect settings. try the router at your friend's house. if it works then its not your router. download a software called network stumbler, install it, to run it in vista right click it and click run as administrator. find the channels your router and other routers in the neighborhood are using. if they are the same then its an interference issue and if not then your router has incorrect settings.