You don't need to run explorer.exe as a different user just to connect to a network share with different credentials.
In an explorer window vous pouvez cliquez sur "Map network drive", fill in the path and and assurez-vous to check "Connect using different credentials". Quand vous cliquez sur le finish button you will get prompted for the credentials you want to use to connect the current share.
Vous pouvez aussi accomplish this with the net command on the ligne de commande.
net use x: \\server\share /user:testuser@example.com password