Originally Posted by philbar71
got a higher wattage power supply
no this is nothing to do with the power supply.
All usb ports provide 100mA of power as standard, but can go to a maximum of 500mA.
"The USB specification provides a 5 V (volts) supply on a single wire from which connected USB devices may draw power... Initially, a device is only allowed to draw 100 mA. It may request more current from the upstream device in units of 100 mA up to a maximum of 500 mA."
1) Go to control panel > system > device manager and find the usb root hubs and check there are no options to play with.
2) Also check that you can't connect 2 usb cables to the hard disk.
3) Failing that then check the WD site.