Here is what I see. I'm running W8 as VM and did expand drive couple times. I just work on this PC(software development) and it's constantly rising. There is also no connection between "all files" space and what "My computer" showing.

Here is what I see. I'm running W8 as VM and did expand drive couple times. I just work on this PC(software development) and it's constantly rising. There is also no connection between "all files" space and what "My computer" showing.

Selecting all files and showing properties skips files where don't have access to. Run TreesizeFree (as admin) and look which folders eat most space.

Now delete or move data that you don't need on drive C:\