GET BACK HIDDEN DRIVE AGAIN IN MY COMPUTER

Start->Run->Type cmd and enter.

In command prompt type disk part and hit enter.

Then type list volume and hit enter.
       It displays drive details.

Drive letter which you want to get back.
If you want to get back volume D,type select volume D and hit enter.
       It appears select volume.

After that type assign letter D and hit enter.

Restart computer once.