Examples:
- Run the RegEdit of Windows as normal user on Windows 10/8/7/Vista, without elevation. In this mode, you'll not be able to access or modify Registry keys that require admin rights.
- Run the RegEdit of Windows as SYSTEM user on Windows 10/8/7/Vista. In this mode, you'll be able to access the HKEY_LOCAL_MACHINE\SECURITY key.
- Run a program with a user of another running process.
- Run a program in high priority.
- Run a specific instance of program in Windows XP compatibility mode, without making global changes in the Registry.
- Run a specific instance of program with different PATH environment string, but without modifying the PATH string of the entire system and without using batch files or command prompt window.
- Run a program with a full set of environment variables you choose, ignoring the system environment variables completely.
http://www.nirsoft.net/utils/advanced_run.html