Many times our Hard disk runs outta space and we have to delete some data space or the other for no reason. After tat i found a working and an awesome way to save ma hard disk space. I used a software named KGB Archiver. KGB Archiver , an open source compression tool like 7zip and UHARC with an unbelievably high compression rate .It uses AES-256 encryption to encrypt archives . Well by this method i Converted Windows XP OS which is somewhat around 697Mb to 6Mb.
The disappointing thing with KGB Archiver is due to its high compression rate its minimum hardware requirement is high ( recommend processor with 1,5GHz clock and 256MB of RAM ) and the time required to compress and decompress the file is high.