exe and navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList. It lets you browse, look up, select files for free. How to Change File Extension in Windows 10.
It looks like you need instead at least contribute permission on the file container in order to rename it. This tutorial contains instructions to rename the user profile folder in Windows OS. Step 2: Select Disk Management from the menu. Case 3: Disable Third-Party Startup Programs from Using the File.
Log on as a different user, rename the profile folder and remove the profile from the profile list in the Windows Registry. I would assume then that when the file is an attachment in Outlook Express, that you are trying to open the file using Internet Explorer.