I am currently trying to clear up space on my computer hard drive and came across storage numbers that don't match up.
I'm using a 100 Gig SSD. Below is System info but I don't know if that is necessary.

When I click properties of the C drive here is what it shows.

When I select all the files and folders in the C drive here is what it shows below.

Right now it looks like there is about 30 Gigs of space unaccounted for. I have hidden files shown so I don't believe it is that. Most of the links I googled had to do with files hidden in the Windows folder but was able to find those files manually on my computer (Mine were smaller in size though than the ones listed). I ran CCleaner and did a disk clean up already, also. Is there anything else I can do to find this files or are there files in the operating system that are always hidden?
Sorry if this is a dumb question but I've spent 4 hours on google and have no clue what else to do. Thanks and let me know if you need anymore info.