When i connect my external hard drive my pen drive doesnt get connected

[ritesh1201]

When i connect my WD 1 TB hard disk my pendrive doesn't gets detected....
Can anyone help pls...

 

[phil22]

It's probably because there's not enough power at the USB ports to drive both devices at the same time, in which case you need to buy a "mains-powered USB hub" like this:
http://www.amazon.co.uk/Port-Mains-Power-Supply-Cable/dp/B002LPVO66