iMac Uncategorized HDD.

Hello,

I own a Mid 2011 21.5' iMac, I have had it for some time and its been glorious and still works like a charm. My issue is and its been like this for two years is the fact that it uncategorized the hard drive and therefore "All My Files" does not work, and when I click the  at the top left and go to About this Mac and Storage it gives me the image in which I have supplied below.

iMac

Mid 2011

21.5

Fully Loaded (all bells and whistles)

Regards,

--Jay