Cleaning a hard-drive should be done on regular basis to claim back the space used by unnecessary temporary files or removed programs. It’s not an easy task to run a clean-up if a user have many programs to maintain because every application are accessing the drive and adding temporary files that will use small amount of space but will take a lot of space overtime. Another reason to clean the drive or system on regular basis is to protect our sensitive data for being retrieved or locate by spysites, spyware or other users. It is also to secure our private information against hackers, hijackers and other type of snoopers or spysites. The widely-use and recommended program to do the entire optimization and cleaning task on a system is the freeware utility called CCleaner (CrapCleaner) by Piriform.
The installation of CCleaner is straight forward and it requires no restart to start using the program. There is no additional requirement to install CCleaner e.g. Microsoft .NET Framework, Sun Java Runtime Environment and it can be installed on Vista, XP and older editions of Windows. You can run CCLeaner in any one of 35 different languages.
Users have the option to install it using the CCleaner's standard or slim installer. There’s no difference with the said installer other than the standard installer bundles 
third party software, Yahoo! Toolbar - and that's why CCleaner is listed in the Calendar of Updates’ Installers Hall of Shame. Many users do not want to have unnecessary component on the system and it's odd to see a system cleaner to bundle with such. Good thing is Piriform continue to provide the CCleaner Slim installer so I will continue to rate this section as excellent for they understand that there are users who do not like any unnecessary programs in installers.
When I let EULAlyzer to analyze the End-user License Agreement (EULA) of both installers, the analysis result show there were no interesting words and phrases in the slim installer of CCleaner while the analysis for the standard installer is there were many detected interesting words and phrases. Why different analysis by EULAlyzer? Simply because there’s third party EULA that is not in any way related to CCleaner and this third party EULA should be reviewed carefully by any user before allowing the installation.
CCleaner program updates require no removal of older version so that the program settings will remain. Also, users have the option download a portable edition of CCleaner or make the already installed CCleaner as portable (please see the section below under recommended settings for details in making CCleaner portable without having to download the portable edition).