In order to re-install software on your computer, first you need to uninstall it. If you delete the software first, there might be some files that software created when it was installed. To uninstall software you need to go to Start > Control Panel > Programs and Features (on Windows 7) / Uninstall program (in Windows XP) and select the program which you want to uninstall. After you did this you can re-install the software.
