Where is the rest of my memory?

[a5ado]

Ok, so I was looking through my computer trying to account for all of my memory. I searched through all of my personal files to make sure they added up to the amount of the "C:/Users/myusername" file (myusername is my username, but not really). Anyway all of my personal files account for the memory taken up by "C:/Users/myusername" and the "C:/users/public" folders. Then I figured another chunk must come from program files. So I added up the "C:/Program files" and "C:/Program Files (x86)" folders (All of this is in terms of GB btw). And I right-clicked went to properties to find the sizes, I didn't just mouseover. Anyway so then I added the size of the "C:/WINDOWS" folder. So I found that:

C:/WINDOWS + C:/Program Files + C:/Program Files (x86) + C:/Users
= about 116.8 GB.

I have a 220 GB harddrive, and it says I only have 58.4 GB free. So my question is, WHERE THE HELL IS THE OTHER 45.8 GB ??? It is completely unnacounted for and I am very upset because I should have a lot more space. What is going on? Also the windows file is 21 GB which is ridiculous but oh well. Does anyone know why this is?

[gazzoid]

Downloading updates and installing creates fresh restore points everytime,so i went to disk clean up clicked "FILES FROM THIS COMPUTER" then in the "more options" tab clicked system restore & shadow copy".this deletes all but last restore points.it freed up 21 gb on mine.!!!!!MAKE SURE YOUR OS IS WORKING FINE BEFORE DOING THIS"