I see that my c:\ disk space used is 90 GB out of the 99.9 GB capacity as seen in Disk properties. I have done a disk cleanup, emptied recycle bin and emptied the contents of temp folder. When I add (sum) the hiddn folders and the unhidden folders'sizes in C drive like Program Files, Program Files(x86), Windows, Users, etc, it sums up to 65 GB only. So, how can I find where the remaining 30 GB is consumed. Any inputs / suggestions?