Thanks, but could you be more specific
In Environment and WindowsIdentity class I didn't find nothing really useful for my purpose, but probably I don't know where exactly I need to search
I found how I can get the current user, or the user running a process, but not if an user is logged
An example: I know that in my PC exists the user "John", how can I know if is logged on? Doesn't exist a simple function to get it?