There are many different ways to clean unwanted files from your computer. Unfortunately, not all of them are safe. Here are a few tips on how to get the junk off of your computer without ending up reinstalling your operating system.
Open Windows control panel and click on the Add/Remove Programs icon. Look for programs you don't use any longer. Use the uninstaller to remove the program. In most cases, there will be some files left over. Navigate to your My Computer folder and manually delete these, or make a note of them and delete them when you're done uninstalling unwanted programs.
Download Revo Uninstaller from Revo's website. This is a safe free program which will make it easier to uninstall programs which do not show up in Windows Add/Remove Programs. Once you've installed and run the program, simply browse through the icons to determine which programs you would like to remove from your computer.
Download CCleaner from their website. This excellent free program can quickly, safely and easily clear the deadwood off of your hard drive. CCleaner looks primarily for temporary Internet files, cookies, Internet history, index.dat files, recent documents, temporary files, files in the recycle bin and memory dumps, all of which are safe to delete. The safest options are pre-checked when you open the program. These are also the most common unnecessary files which tend to take up space on most people's computers.
Navigate to your My Music, My Pictures, My Images, My Videos and My Pictures folders. Multimedia files take up an enormous amount of space. If there are any photos, scans, videos or music files which you no longer use, or which are duplicates of what you already have in another folder, you can safely delete them. Also you may want to transfer some of these to a CD or a flash drive if you would like to take them off of your computer.
Delete any downloaded files, beginning with anything which is old or has a very large file size. In your downloads folder or folders, right click on the window and select Arrange Icons By and then select Size. This will allow you to see which files are biggest and need to be deleted first. Don't hesitate to delete older files that are 500 megabytes or larger simply because they took a long time to download. Chances are they're outdated and will have to be re-downloaded anyway.
To clean files off a Mac, download and install Onyx, a free program designed for Mac OS X.
Avoid registry cleaners, and never make edits to the system registry unless you're prepared to reinstall your operating system.