batch file to deactivate photoshop

You can start Photoshop.exe like any other application from a bat file.  You may need to know the its not already started first. You should be able to pass Photoshop a file to open and have an open document event setup in the script event manager and do something like deactivate when a particular deactivate file is open.  A script should be able to close down Photoshop but I know of no way to to tell Photoshop set a a return code that the starting bat file could test for. So the deactivating script would need to initiate the activation on the remote system perhaps through a socket connection to a waiting server on the remote machine.  There are at least three machines involved. Your two Photoshop machine and an Adobe Activation server.  Its a complex process to automate.  How would you handle thing like Adobe servers not responding or communication between your machines.