I have the same problem. I am using a speedtouch modem and when I contacted my support centre they informed me that unplugging and immediately re-plugging the modem in was the only suggestion they could give. I have tried several methods such as leaving the power cable switched on all night but switching the computer off. Leaving the web page running and then turning the computer off so that it saves the program I am running before cutting off. Turning the power on at the mains and waiting a couple of minutes before switching the computer on. The success has been variable but so far no permanent solution. I suspect it has something to do with the USB power supply and the modem power requiremnts, but what, is beyond me. Like you it is annoying but not disasterous. Once connected it works perfectly.