Can't re-partition "Free Space" on Hard Drive

Hey guys,

I tried to dual install Linux on my Hard Drive, which required partitioning my HD. After the installation failed I was left with about 90GB of "Free Space" that I can't partition back.

What is it that's preventing me from adding it back to it's normal state? What can I do to change it back?

Everything is backed up and I have access to everything offline and in Dropbox. So i'm not worried about wiping it or anything. Also if anyone can point me towards reading material so I can understand how the drives work, id appreciate it!

Thank you! (Here's some pics of what its looking like)