I just a bought a segate 100 gb portable external hard drive. It came with a Y type cable. The two ends are USBs to the computer.

The manual says that if the drive doesn't have enough power from one cable, then connect the other cable too. The first USB end (green) is POWER+DATA and the other end (blue) is POWER ONLY. There is no mention of what would indicate less-than-enough power. I connected the green end and the hd started beeping and the light blinking. The computer didn't recognize the hard drive either. Then I connected the othe end and then it was fine.

I will try it with the Work computer tomorrow but is this pretty common to have to use two USB cables for Portable Drives?