Problem with my passport hdd portable 1 tb not showing up as a letter urgent

i have a portable western digital hdd portable of 1 tb  but the problem is that doesn’t shows up in computer as a letter only i can see it in disk management as disk 1 as unallocated space and not initialized and when i click in the space that it has with right click only appears offline not online
so i want to know the best software for to recover all the data that i have there i need it urgently doesnt matter if the software is free or i have to buy it

or what i have to do for to have it working normally as it was 
please tell me thanksxxx 

Well here is a free one Recuva http://www.piriform.com/recuva and this from EaseUS is try and buy  http://www.easeus.com/ You can recover 1 gig and buy it if it works for you.

Joe