what if no network card is installed? what if an installed network card is removed? what if another network card (with another chip) is installed? what if the pc isn't connected to any network? (okay, you ruled that out..) what if you have the ip? how do you get the person/place that ip belongs to? ask the isp? do you think that they would give away their customers' name/address? what if the network doesn't belong to the thief(university, internet cafe, hacked/open wlan)? what if the device was already sold to someone else? even if they would be forced by law to give out the address..what would you do then? go there by yourself and kindly ask them to give the hardware back? ask for a house search (that the police would have to do)? i doubt that some network card pinging something is a proof for anything.
there are special programs and firms that include data destroying software into the os and bios. if a stolen device is connected to the internet (and the software is still installed and the ports it uses are not blocked (that's what those firms don't like to talk about)) it connects to a server. now the destruction routine could jump in..an ip detection routine, too. but still they won't have a name or a place.
technically however it is possible as long as the nic remains in place and there is a connection to what's called the internet. Holger