If you are still using the Black Teryon modems, the prob is with the modem.
Have same setup as you with the modem keep disconecting.
Phoned NTL and they sent an engineer round to change modem for the new type they use.
I thought it might be my Eth card or cable and changed them just in case, but this made no difference.
New Modem solved the prob completly.
The reason why is that the old modem has such a narrow Db drop out signal +-.4 Db that any disruptance in the line signal caused it to fail and disconct. The new one has a +- 1.5 Db allowance, and considering the attenuation is only 4-5 db to start with it allows a much higher variation to occur before drop out occurs.
it says a network cable has been unplugged then waits a little while then connects again. also what measures can i take to improve my internet speed without upgrading. i know clearing internet files (cookies) may help but what else?