Lack of power from the USB socket is the problem, (If you look at a lot of USB HDD they have 2 USB Type A Plugs thus doubling the power to the drive) however adaptors are available that can combine the power of 2 USB sockets, so it may be worth trying one of those. Here is one example http://www.pccables.com/70650.htm

Hope this helps

Bill
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English Riviera:
Live entertainment, Real Ale, Great Scenery, Great Beaches, why would anyone want to live anywhere else (I�m definitely staying put).