Hi,
if you want to list all Users which are currently logged on to the box use the query command.
List all sessions
c:\> query session
SESSIONNAME USERNAME ID STATE TYPE DEVICE
services 0 Disc
console 1 Conn
>rdp-tcp#0 user1 2 Active rdpwd
rdp-tcp 65536 Listen
Or list all users
c:\> query user
USERNAME SESSIONNAME ID STATE IDLE TIME LOGON TIME
>user1 rdp-tcp#0 2 Active . 21.02.2015 19:42
You can also list the processes of the user
c:\> query process
USERNAME SESSIONNAME ID PID IMAGE
>user1 rdp-tcp#0 2 6076 taskhost.exe
>user1 rdp-tcp#0 2 6592 rdpclip.exe
>user1 rdp-tcp#0 2 4840 dwm.exe
>user1 rdp-tcp#0 2 4680 explorer.exe
>user1 rdp-tcp#0 2 7092 vmtoolsd.exe
....
Michael