I have been a BT ADSL user for about 15 months and at first had problems with the modem and having to remove and reconnect the USB plug on the Speed Touch.
The fix to the problem is simple and has worked for the last 10 months without the need to unplug the Speed Touch.
You need on boot up to set Outlook Express to boot up as well, and then set it to check for emails every minute, this stops the modem from falling asleep, this fix took BT and Alactel four months to work out and BT gave me 6 months free connection for the trouble I had.