When the client system is crashed, you would first want to repair it. You can use IDE-redirection to boot from a remote good image, with serial-over-LAN to interact with the client in a console window. With this setup you can remotely diagnose the system problem. If it is a software issue, you can remotely repair it now that you are connected. If it is a hardware problem you will need someone to go to the system to fix it.
Now that the system is fixed, the data recovery software can be run on the client's host OS.
