Clean Windows registry with CCleaner
Registry cleaning does not usually improve performance noticeably, but it does resolve and prevent trouble with outdated/orphaned entries that cause error dialogs ("file or folder not found" is the most common example). You can perform this step once a month to take good care of Windows registry.
If CCleaner is not already running, open Start menu or Start screen by pressing Windows Key on keyboard.
Window XP users should choose All Programs, find CCleaner folder and click CCleaner:
Windows Vista and 7 users should type "ccleaner" into Search box and click CCleaner in search results.
In Windows 8 and 8.1 Start screen, type "ccleaner" (you do not need to open Search charm) and click it in the results. Touch-screen users should swipe in from the right side and tap the Search icon.
After opening Registry tab from the left, click Scan for Issues button. Those who want to be extra safe, can untick the Unused File Extensions check box, but only very few programs run into minor trouble after cleaning unused extensions.
You will probably get a quite long list of issues when running CCleaner for the first time. Click the Fix selected issues... button.
CCleaner will ask if you want to backup changes to the registry. This will create a backup of the issues detected in Windows registry. Click Yes.
Save the backup file to your My Documents folder (Windows XP) or Documents library (Windows Vista, 7 and 8/8.1) by clicking Save. In case you experience trouble after removing the listed items from registry, you can simply double-click this backup file and import all the deleted items back into registry.
Next, click Fix All Selected Issues and CCleaner will remove invalid and orphaned entries from Windows registry:
After the cleaning is complete, click Close:
But you are not done yet!
Repeat the process by clicking Scan for issues button again. Most probably you will see another, much shorter list of issues. Because CCleaner does not cross-reference previously deleted items, there are usually more useless entries in Windows registry. CCleaner finds them only during second scan.
So please repeat the process of clicking Fix selected issues, backing up changes to your My Documents folder or Documents library and clicking Fix All Selected Issues and Close buttons.
Then click Scan for issues... for the third time and you should see "No issues were found" message. If not, repeat the cleaning process and do another scan until you see the "No issues" message.
As Windows registry is stored as multiple files, it gets fragmented during cleanups and program installation/uninstallation. This might hinder computer performance somewhat, so please see the Defraggler tutorial for information on how to set boot-time defragmentation of most important system files.