weak networksignal / slow connection

i am sharing a dsl connection among the resident in the building. the connection is shared through router & switch. i am checking the connection with my laptop. the connection works fine if connected to a router or a switch. on the other end when i check the connection by a lan tester it shows there is a flow of connection, but when i connect my laptop to the networks it doesnt work. i TCP/IP is set to gain IP address automatically. When i check the lan status on the computer it shows bytes received & send which is very slow and i cannot access the internet , what would be the solution.