Multi user login commonly know as Concurrent sessions gives you the advantage to allow multiple users to login to the same computer using a remote computer without disturbing other users using it.
Concurrent sessions is a feature in server editions of Windows that lets more than one user to log on remotely and use the server at the same time. By default in Windows 7, Windows Vista and Windows XP when you connect to a computer using Remote Desktop it forces the person physically using the machine to loose his session.
If you have concurrent session enabled on your Windows machine everyone can access the machine using Remote Desktop without hampering other users work.
How to enable Concurrent Sessions on Windows machine
1. Download the Universal Termsrv.dll Patch by DeepXW and unzip it.
2. Prefer manually backing up original Termsrv.dll from C:\Windows\System32 folder
3. Right click and Run as Administrator the appropriate patcher exe depending on your OS version
For 32bit (x86) select UniversalTermsrvPatch-x86.exe
For 64bit (x64) select UniversalTermsrvPatch-x64.exe
4. Click the Patch button to patch the DLL and click OK on the success window
5. Restart your machine for the changes to take effect
I have tested this and it works fine without affecting your Windows OS or any other application. Multiple users are able to access the machine using Remote Desktop.