My wifes laptop is trying to use DUN ins...

My wifes laptop is connected to our home network via a network cable and then on to the internet via a router. Recently, her laptop has started trying to connect to the internet when surfing via dial-up networking connection instead of the network card connection. cancelling the dial-up connection results in the network connection then being used, but it happens every time the browser opens a new page (ie every time it attempts to access the internet and not the cache). She needs the dial-up connection because the ISP hosts webpages of hers, and have to connect via their server to maintain them, so removing the dial-up connections is not an option.