Internet keeps dropping...

Every so often, but mostly when I close my browser, my internet just stops working on my computer for a while. I have a tp link receiver, and when the internet drops, it doesn't say that my connection was lost on my networking thing. It usually says "Can't connect to DSL" when this happens, but then it just says that it cant connect to the internet. I have att and a crappy wireless modem that they sent. I need to know if there is something I can do to fix this, or if I need to change my provider. Thanks!