There are three main ways of cleaning up files and programs on a computer. One is to uninstall programs that are no longer needed and another way is to delete unused files.

Follow up:

Deleting Files

Some files can be hard to find but lets take a look at the obvious places first. First check My Pictures, My Videos, My Music, and My Documents for any files that are no longer needed. If all of your files are still needed then consider backing them up on CDs, DVDs, BluRay Disks, or an external hard drive. If the files are very important to you such as family pictures or business files then back them up onto multiple places because hard drives can fail and CDs can be lost.

For those files that cannot be found so easily a search will do. Click start and inside the box that says Start Search (with in Vista) or find files in XP. Now type the extension of the types of files you would like to find. If you want to find video files, type in "wmv", "mpg", "avi", or "mov". If you want to find pictures, type in "jpg", "bmp", "png", or "gif". If you want to find documents, type in "doc".

Uninstall Computer Programs

In Vista or XP click the start button in the bottom left corner of the screen and go to the Control Planel. Click Classic View on the left side of the window that will open. Now double click "Programs and Features" icon or the "Add remove Programs" icon.

To uninstall these programs, click them, and click uninstall. This will uninstall a program you have selected. Some programs my not show up in this utility but usually can be found the the program files directory on the C drive.

Reformatting the Hard Drive

The computer can be easily cleaned up by reformatting it. But first make sure that all of the programs, files, website bookmarks, and any other data on the computer is backed up before the computer reformats and Windows is reinstalled.