Missing storage space

I have a 1tb wd my book. Recently we moved our computer room to a different room in the house. When we plugged everything back up the exact way it was, my “my book” is only showing it has 40gb of space total??? Can anyone help and may give me some ideas on getting the rest of my space back? I’ve already formatted it and it still shows it’s a 40gb instead of 1tb. Help!

When you formatted did you delete the old partition/volume? http://wdc.custhelp.com/cgi-bin/wdc.cfg/php/enduser/std_adp.php?p_faqid=3865