Hi there,
Make sure you are in the test port and have tried another filter.
Then you need to find out if the line is causing the drop or the hardware. Easiest way is to start a ciouple of ping tests.
Hold ctrl and press R then type 'cmd' into the run line. In the black window type 'ping 192.168.1.254 -t' (assuming its the BT hub) and hit enter. This will start a continuous ping to the router.
Open another black window by ctrl R and type 'ping 8.8.8.8 -t' and this will start pinging googles dns.
Leave them both running and when the connection drops check which one stops replying. if it's both then your hardware or internal connection to the router is failing.
If google ping drops on it's own then it's your line.
If it is the line then call the helpdesk and request an engineer. They will probably still run tests and tell you they could charge for the visit. BT is responsible for the line up to the main test socket so as long as you are in there and using BT equipment there should be no charge....you still have to agree though.
Hope this helps.
Thanks.