Who knows if it applies to you. Inside Windows settings there are "power" settings for many devices. Find those and turn the off.
Here's an example. Sorry I don't own your setup so I won't be able to tell you where to look.
See "Disable power management" at http://h10025.www1.hp.com/ewfrf/wc/fastFaqLiteDocument?lc=en&cc=uk&dlc=en&docname=npg40836
There are similar boxes for other hardware.
Bob
We have 2 users travelling with laptops. One user has a broadband card, and the other is tethered to a Blackberry. Both are using Verizon as the carrier. When working on-line, both experience issues with the devices powering on and off, and either as a result or resulting in the connection being lost.
Is this because
A) a power signal is causing the device to lose the connection and perhaps the device is resetting in an attempt to recover the signal
B) the users are probably working on battery power, and the battery power cannot maintain the power for the devices
C) something else altogether?

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