Hi,
I had the same problem with my MicroClient Sr from Norhtec, for me it was the power supply that was broken. The supply wasn't able to deliver more current than needed to flash the LED. I tested it by measuring the output voltage before and after connecting a resistive load (the load corresponded to less then half the rated output power), with the load connected the output voltage fell below 1 v so I considered it as broken. I bought a new power supply and then the MicroClient worked again. I believe that the power supply is a bit weak if all the USB ports are constantly used, a friend of me had the same problem as well and that was also solved with a new power supply. I bought a standard stabilized 5v 5A supply and used the connector from the old supply to connect (I had to measure to get the polarity of the cable correct).
Hope that this can help you
/Jon