I tried several times to uninstall the 1202 version, and install the 908, but I always failed. But in the last try, I finally did it! Now I'm gonna tell you exactly what to do in order to uninstall the 1202 version, and install the 908, without any problems.
1. Go to Add-or-Remove-Programs, and uninstall "Windows Live Essentials" (select every Live feature you see in the list which comes up).
2. Go to Add-or-Remove-Programs, and uninstall "Windows Live Sign-in Assistant".
3. Go to "Start Menu -> Run" and type
msiexec /x {505DF7A3-88D5-4DD6-9AD5-C98C2ED0CEC4}
4. Go to "Start Menu -> Run" and type
msiexec /x {F69E83CF-B440-43F8-89E6-6EA80712109B}
5. Download and run Zap Messenger from
here.
6. Download and run CCleaner from
here. Clean the registry with this tool.
7. Download and run Windows Live Messenger 908 Installer from
here.
8. Download and run Contacts.msi from
here or
here.
9. Download and run wlc.msi from
here or
here.
10. Download and run wllogin.msi from
here or
here.
Now you should restart your PC, but it's not necessary to. I did not.