You're confusing Windows Messenger 4.7 which is built into the Windows XP
Operating system with MSN Messenger 7.5 which is a separate instant
messaging program offered from Microsoft. You do NOT need to uninstall
Windows Messenger 4.7, the two messaging programs can co-exist together.
Matter of fact, if you use Remote Assistance, MSN Messenger 7.5 and Windows
Live Messenger need Windows Messenger to use this feature.
If you would like to disable Windows Messenger from running at the same time
as MSN Messenger, open Windows Messenger/Tools/Options/Preferences.
Un-check "Run Windows Messenger when Windows starts" and "Allow Windows
Messenger to run in the background" and select OK.