Dear Sir,

To remove Windows Live Messenger completely from your system using the Windows Installer Cleanup Utility just check it here:

http://support.microsoft.com/kb/290301.

Then you can re-install again

Thanks

WRONG SECTION!!!!!

Perhaps try downloading Ubuntu from
http://www.ubuntu.com/getubuntu/download
then make a cd of it by double-clicking on the iso file, this guide might help
https://help.ubuntu.com/community/BurningIsoHowto
i tend to find the cheapest "write once" cds that you can only get in blocks of 10 or more are better for this than more expensive cds and dvds tend to be really rubbish for this. Anyway once you have the cd then boot up from it to the menu with "Try Ubuntu without changes to this machine", if you don't get that menu then this guide might help
https://help.ubuntu.com/community/BootFromCD
Choosing the "Try Ubuntu ... " option should get you to a working desktop which we call a "LiveCd session", if it works ;) Most versions of linux have this feature although they don't all have such a fancy menu. Ubuntu's LiveCd has firefox on the top taskbar and should have worked out your internet connection so having got a LiveCd session working you should be able to surf around and check that Ubuntu is going to work easily on the machine. Once you've done that then a dual-boot is better than wiping off an existing working OS, even if that is Windows ;)
https://help.ubuntu.com/community/WindowsDualBoot

Good luck and regards from
Tom :)