Download Treesize Free from http://www.jam-software.de/treesize_free/. Install it, run as administrator, allow it to do changes (it won't) and all your questions will be answered.
Then run the Disk Cleanup Wizard, in its advanced option ask it to delete all but the latest restore point and run again. Notice the difference.
DON'T do a manual delete in that System Volume Information folder!
HDD of my PC (500 GB) is partitioned in to 3 parts, in which 'C' drive (50 GB). Apart from the OS (Windows 7), "My Documents" etc. nothing much is kept there. The available space in 'C' drive shows 2.5 GB only (i.e. 47.5 GB is occupied) where as the total of space occupied by individual folders contained in it is 35 GB. Why this difference of 12.5 GB and how can I see the contents of this 12.5 GB so that some unwanted files can be deleted ? I understand that some space is taken by the system, but can it be to the extent of 12.5 GB ?
Hope to get a clarification at the earliest.... B.N.Bhattacharya (firstname.lastname@example.org )