Shoutbox

Well, once I was trying to uninstall a bunch of things. Loooooong time ago.
I accidently pressed the uninstall button to either messenger plus live or just windows messenger live, I can't really remember which one, but i pressed cancel as soon as I could, but I still think some things were deleted. Ever since, every time I log into the computer I keep getting a window message saying this:



Then after I press OK, it takes me to this

http://www.msgpluslive.net/

The downloading site. But I already have it downloaded, and it works just fine, so why does it want me to re-download it?
Anyways, I have re-downloaded it, but it does nothing to solve the problem, and it that annoying window keeps popping up every time I log into the computer, so what should I do? Does anyone know how to solve this problem?
I haven't a clue why it keeps doing this.