I had a Emachine, and a Dell back when Win7 was out in the wild, and both did the same thing, one for Consumers the other Corporate (which pissed us off and forced us to purchase Site License edition at the time than the preload Dell we had). If you don't know that time period, people figured out how to 'open the side panel' and some were being stupid taking out a memory stick or drive and taking it home or selling them off. So they built into the case the 'case been open' alert function that interacts with the BIOS (nothing to do with Windows). So when Windows would load, being OEM, it would take the BIOS info and apply it.. is this the OEM CPU, yes... is this OEM Mobo.. yes.. is this OEM case.. NO - ERROR! This is not the original equipment, Windows is only authorized for original equipment, and refuses to do anything more than alert you in the boot sequence of the problem.