Many people have been having problems with the standard Bt Voyager 105 modem supplied for free by most adsl supplied in the UK.
The problem seems to be that the modem uses more than 500mA when running at full speed. Most USB ports / hubs only allow 500mA to be used, hense the computer crashes with a power surge warning when using the modem at full speed.
An easy fix is to solder a 1-2amp @ 5V regulated powersupply directly to the modem, isolating it from the USB port / hub. After this the modem can suck as much power as it needs, normally in excess of 500mA if my multimeter is to be trusted.
Instead of dismantling the modem you can solder the 5V power supply directly to the +5V and ground lines of a USB cable. Make sure you leave the 5V line disconnected that goes back to the computer. If you reconnect the ground shrouding you will preserve the noise filtering as well.
You might also notice that download speeds increase.
The power savings options still work incidently.
Doupt it will help many ppl here, but its a simple thing to do instead of buying a new router / modem.
Still, the modem does suck...