Try using the Windows Update feature of the operating system and downloading all available updates. This is not only good practice for managing your system, but will also ensure that you have all the prerequisites needed for installing Windows Live Messenger.
As part of these updates you will be offered 'Windows Live Essentials' which encompasses Windows Live Messenger.
Also, please take note of the forum rules, most specifically: "Messages should be typed and formatted in a way that others can read and understand. Usage of ALL CAPITALS, aLtErNaTe capitalization, poor spelling/grammar, and ugly fonts is discouraged". Thanks