While Windows Disk Cleaner does quite good job at removing some temporary files, there are probably more non-Microsoft programs on your computer that have some leftovers and unneeded stuff on your computer. Also, every user tends to install, upgrade and uninstall software, and this might leave many unnecessary entries in Windows Registry - a place where all information about hardware (monitor, sound card, video card, mouse, etc), software and user settings is kept. When registry contains entries to programs and files that do not exist anymore, Windows might start slower or display errors.
CCleaner (also known as Crap Cleaner) is a free program for cleaning up such temporary files and unneeded settings in Windows registry. It can also detect and remove duplicate files, securely wipe free space or whole drives, manage Windows startup items and web browser add-ons. Since version 4.18, CCleaner has a real-time monitoring tool that offers to clean up temporary files from time to time.
There is also Android version of CCleaner available.
First, go to CCleaner download page and click Piriform.com in the CCleaner Free section.
After downloading and launching the setup file, CCleaner Setup Wizard begins with asking for the language to use. English is fine, so click Next here.
In Install Options window, leave all check boxes ticked and click Install.
You might or might not see an offer to install some other software after clicking the Install button. In my case, it has randomly been Google Toolbar and/or Google Chrome. Do not install any software you do not really need or know much about. The word "Free" means nothing useful in such cases!
Depending on the options available, clear the Install Google Chrome as my default browser, Also include Google Toolbar for Internet Explorer, Install the free Google Toolbar along with CCleaner check boxes. Then click Install.
After setup finishes, clear the View Release notes box. This is for tech geeks only.
If you want to run CCleaner right away, leave the Run CCleaner check box selected.
Click Finish to exit setup process.
As CCleaner checks for updates automatically, a new version notification window appears from time to time. Use the Click here to download button to get the latest version.
Your default web browser will open a Piriform sales page, scroll down and click the No thanks button to continue using the free version of CCleaner.
The rest goes exactly as in downloading and installing part.