(Almost) No more space on SSD?

[Mom]

So, I recently went looking for a file inside my downloads folder, but stumbled into the fact that I only had 7 GB left on my 840 120 GB SSD [Picture number 1]. Now, this is odd because when I checked the week before, I was fine at around 60 GB of free space. And it is not just windows that has gone to crazy land, Samsung Magician agrees [Picture number 2].
I went looking for whatever is using this much space, but didn't find it. All the files inside the drive (C:) only fill up 51 GB according Windows, which would match the 60 GB of free space i used to have. [Picture number 3] 

Cleaning the drive will only save 13 GB.

Any ideas on what is causing this and how to fix it? - It is just Windows being crazy?

If it is of any use, my specs are:
i7 4770k - H100i to cool it.
GTX 770

Msi G45 motherboard

Western Digital 1 TB Blue

Samsung 840 120 GB

Thanks in advance!

[theninja35]

Have you accidentally been installing games or downloading things onto it?

 

Interesting though because 20GB of random space was just put on my drive while I was at school.

[Sequence]

Use a tool called space sniffer it will show you what it taking up space. 

[Mom]

I've just downloaded WinDirStat and it says Size: 59,2 GB which i suspect is the size of all of the stuff on the drive.

And I haven't been downloading, moving or otherwise handeling any large files recently. And definitely not something the size of 50 GB.
 

[Mom]

And Spacesniffer tells me the same thing

[blu4]

Give cleaner a go. That should free up some spac. I just can't stand space sniffer for some reason

[blu4]

I meant CCleaner. Can't edit.

[TDP_Equinox]

Boot into something like the hirens disk and check the SSD for SMART errors or otherwise. 
Also, check in partition manager to see if something is strange.