loss of broadband

hi there,can any help,Ive got a belking wireless router set up ,Im on pipex broadband,pc besktop, If I leave my computer for about 10 min after Ive been on the internet the broadband connection goes off,and I have to reboot the computer to get connected back to the internet,Ive tryed going into tools ,internet options,cant find anything there to help,any help please,birdman1

just to say the computer is connected by a ethnet cable to the wireless router,so all is ok at that end,birdman1