Help WIN+E shortcut to explorer doesn't work!

[duduisback]

Hello Guys,

I got the exact same problem : my shorcut Windows+E doens't work with the exact same message (but in French in my case): "Not specified error"

Also, on the desktop shortcut, the error message is

[Window Title]
explorer.exe

Contents

Aucun programme n’est associé à ce fichier pour exécuter cette action. Installez un programme ou, si c’est déjà fait, créez une association dans le Panneau de configuration Programmes par défaut

The only way to open explorer is to open the "my computer" Icon...

I work for a software editor company and we use lot's of test PC especially with Windows Seven and I got the same problem on some testPCs over here...
But I cannot figure out what can put the system so unstable that way...

if you guys can help me with that... that would be great !

Thanks for your help !