60 GB SSD drive - OCZ Vertex, 30 GB missing

Hello there, this is my first post and I'm glad to be here. Sevenforums has helped me numerous times in the past with similar problems but I have never had to ask for help.

So here I am starting over with a fresh win 7 ultimate x64 install on a formatted 60 GB SSD (:C/). When all is up and running, I have 15.9 GB free space.
I enable show hidden files and selects every folder on my SSD drive, it says the selected contents take up 15.4 GB.

This is where I take advantage of my mathematical skills and come to the conclusion that I have ~25 GB not showing up anywhere.

By the way, the drive shows up as having 55.90 GB capacity. I have moved the user folder to a second drive and disabled indexing on (:C/) but the problem persists.

I have been searching and searching, some people mention hibsys, pagesys and corrupt recycle bins but I can't make any sense of it.

Thanks in advance

Did you check in Disk Management ? Maybe some unallocated space ??

E: is just a bootable USB

I found out that pagefile.sys and hibfil.sys were using alot of space. I have 16 gb RAM and it is recommended to have a pagefile.sys 1.5 to 2 times larger than that.

But I found it out by using TreeSize - Disk analyzer program with a 30 day trial. Try it if you have disk problems...

Anyway, this is solved so I thank you stereo for the reply :)