USB extension Cable Problems

[Donniegate]

When I try to run my bus powered Lacie 40 Gig exernal H/D, (which I use on my Notebook), on my PC with an extension cable it lights up but isn't recognised.
    If I plug it directly into  the USB in the computer it works fine. I want to use the extension cable to do this as it is very inconvenient to have to connect it in the USB ports at the back of the PC.
       The H/D is USB 2.0 and the ext. cable is also USB 2.0
              Hoping someone can help.

[fool2cool]

Try a Different extension cable, it could be faulty, if you can check the continuity of each of 4 wires on the extension cable one of the data lines may be broken. hope this helps.