Did you know – you can find out who is logged on to a particular PC on your network with the whoison.exe utility.
To use the utility, save it to your local hard drive or your network drive. I have it saved to the root of my C: drive for ease of access.  Run it from a DOS command prompt, (see example below): Type C:\whoison \\computername
 
Use the /h switch to get a history of users on the PC:
whoison /h \\nameofcomputer
Use the pipe command to send the results to a text file:
whoison …