CCleaner (formerly Crap Cleaner), developed by Piriform is a donationware utility program used to clean potentially unwanted files and invalid Windows Registry entries from a computer. The Piriform website states that as of 25 February 2010, CCleaner had over 450 million downloads.

CCleaner is a freeware system optimization, privacy and cleaning tool. It removes unused files from your system – allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner.

Pros:

• Free software.
• Simple to use product even for newbies.
• Backup option is great.
• Registry cleaning feature works great.
• Selectable scan and history cleaning choices, customizable.
• Supports secure delete

Cons:

• Doesn’t get really deep into your system it seems so, one is left with possibly a lot of registry errors.
• Can be a little too aggressive in some cases.
• Doesn’t catch everything.
• Update could be better.

This product is recommended for everyone, specially using Windows XP. This simply works what it claims.