Have you ever tried to use RunAs to start a new instance of Windows Explorer--with no result, even though you provided the correct credentials? This glitch happens because by default, RunAs first determines whether an instance of Windows Explorer is already running on the system--which is always the case. Therefore, RunAs passes the request to the existing Windows Explorer process instead of starting a new one. You can resolve this issue by selecting Tools, Folder Options from the Windows Explorer menu bar, going to the View tab, and selecting the Launch folder windows in a separate process check box. You can also change the setting directly in the registry, by setting the HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced registry subkey's SeparateProcess REG_DWORD value to 1.
You must set this user setting for the account in which security context you want to start the new Windows Explorer instance, not in the security context of your current account. To set this flag from within your current account's logon session, you can use one of two methods:
Start Internet Explorer (IE) in the security context of the other account. Enter a local address in the Address box to change the menus to those of Windows Explorer, then choose Tools, Folder Options from the menu bar and go to the View tab. Select the Launch folder windows in a separate process check box.
Run regedit or regedt32 in the security context of the other account. Navigate to the HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced registry subkey. Change the SeparateProcess value to 1.