I need to evaluate on which hardware esxi 5 server is installed on. Is there any way to do it - apart from opening the case?
Hmmm... if you dont want to have a ssh enabled or a GUI user, you can use a vSphere client to connect to the server, you should be able to get almost every information abt the box by summary tab, or clicking on Configuration-health status or in Storage Adapters or in Network adapters.
Just for clarification, what hardware are you trying to locate?