Now, I'm not uninstalling MsgPlus!.
I was uninstalling MsgPlus! recently to update to the new version with MSN 7.
I had the directory in my registry set to C:\Program Files\Messenger Plus! 3\MsgPlus.exe
I then had the new version set to C:\Program Files\MessengerPlus! 3\MsgPlus.exe
Now, when I uninstalled, the startup registry wasn't deleted, and it wasn't changed during installation. I would think if the directory for MsgPlus is changed, the startup registry should change also or else MsgPlus! won't start up with MSN everytime MSN is opened. (Plus! isn't in the menu if it isn't on)
I was able to change this by installing in the old directory I had.
Although, I just remembered now, when I uninstalled, none of the files for MsgPlus! were deleted either.
So it would have still worked even if it was uninstalled.