Personal computers slow down, almost grind to a halt, when their hard disk drives are nearly full. If that's happened to your machine, and there's less than 10 per cent of its hard disk drive space free, it could be time to check for duplicate files and delete them.
They can arrive on your machine when a backup program fails to delete the old backup when it creates a new one, and sometimes by accident.
There's many ways to search for duplicate files, but the quickest and easiest way is to use the search utility built into Windows.
You can use it to search for duplicate files across the entire hard disk drive or in individual folders such as your Users folder which stores all the personal profile details and files of each of the individual users who log into the machine. You can also narrow it down further to individual user's folders such as Desktop, Documents, Downloads, Music, Pictures and Videos.
In Windows 8.1 open the Search box by either clicking your cursor on the Search box in the top right hand side of the modern user interface Start screen with your mouse or touching the little magnifying glass symbol with your finger on a touch screen machine. You can also open the Search function by swiping your finger from the right of the screen on a touch screen machine, causing Search and four other Windows 8.1 charms to pop out from side, or placing your cursor in the bottom right hand side of the screen with your mouse.
Or you can just start typing.
In Windows 8 you can only access the Search Charm from the side of the screen since there is no Search button at the top right of the screen. You need to define your search by using the file extensions of the files you are looking for. This is the three or four letter code found at the end of every file that defines its type. Microsoft Word files, for example, are DOC or DOCX depending on software version. Pictures may be BMP, TIFF, JPG or any other number of file types.
The default search location is Everywhere, which includes your machine's hard disk drive and the internet, so you will probably want to narrow the search down to just Files. The other options are Settings, Web images and web videos.
Pressing Enter will display a list of files with the defined extension which you can scroll through and compare and delete duplicates as you go. This rather manual method can take hours if you have thousands of file so you can be more prescriptive. Some software adds the word "copy" to a file that it copies so that you can tell it apart from the original. Try searching for that instead of the file extension.
An alternative is to try similar searches using the Search function in Windows Explorer found from the Desktop of Windows 8.1 and 8 or accessed in Window 7 by clicking the Start button and clicking Search.
It is from here that you can select specific folders to search, rather than having to chug through the hard disk drive. If this all becomes too much the alternative is to run third party file duplication detection software, but be careful with such software as, in the wrong hands, it can delete essential files that are needed to make your machine run.