Problem 2 external disk my passport se on PC with Win 7

Hello please, I have two external drives home My Passport Es 1TB. The problem is that when I connect two drives to a PC so I just read one. When you disconnect one of them, so only just read the other. You do not know how to enable or configure these drives so I can read and join at once. Thank you all

It’s a Windows thing check this post http://community.wdc.com/t5/Other-Externals/Problems-with-having-more-than-one-USB-2-0-WD-2-TB-Elements/td-p/285724
Joe