裝唔到msn...

do u have any msn right now?
and are u the administrator of the computer??

go to "regedit" (start > run > type "regedit" )
find the regedit value, which is the picture said
adn then delete it
if you can't find / delete it
reinstall the window is faster
or call the administrator of the computer

你試下洗機（只是隨口而說，不知意見可否符合個人需要．如有得罪抱歉）