PsLoggedOn, from SysInternals, will determine the who is logged onto a local or remote computer, locally and/or remotely. If you enter a user name, it will search the network.
PsLoggedOn searches the the HKEY_USERS hive to determine whose profile is loaded.
Psloggedon \[-l\] \[\\computername | UserName\]
-l - Show local logons only.
Computername is the name of a remote computer.
Username is the name of a user to search the network for.
PsLoggedOn -l shows that you are logged on locally.
PsLoggedOn shows your local log on and who is connected to your shares.
PsLoggedOn Jerry shows every computer where Jerry is logged on, indicating local or remote.
PsLoggedON \\JSI001 shows who is locally logged onto JSI001 and who is remotely logged on.