Older hdd no longer shows free space

Hi, I used an older hdd in a new desktop using win 7 pro 64 as storage with a second newer hdd and a ssd boot drive.
I had to remove and reinstall it 2 times while building the computer and this older drive has a lot of data on it but the graphic in My Computer shows it having virtually 100% free space (as well in "the properties" section ) It did show the free space remaining at first but no longer, the other 2 drives are fine in this respect.
The files all show up and otherwise the drive is fine but I don't understand why I lost this function or how to get it back.