Bandwidth loss.. need help asap


Dec 8, 2011
In my office there are 8 computers in a network... There is no any special network defines.. Its in simple architecture.. Internet from ISP is connect to router and router to hub and then its distributed to all other computers.. My problem is.. Since last two week my internet has gone to slow. ISP says everything i ok on there side.. but there is problem in my network.. I thing, my be some of the computers are using over bandwidth.. So i want to ask, how can i monitor bandwidth in my network(want to know, which computer is using what amount of bandwidth) and if i can manage the bandwidth as well.... Thanks in advance