To almost surely diagnose client terminals.

If program starting preprocessing is executed for a hard disk drive 16 and it is normally completed, processing execution starting programs that are read out from the hard disk are started. If the program starting preprocessing is not normally completed, diagnosis starting programs that are stored in a ROM 14 or a RAM 15 are started. Subsequently, diagnosis processing is executed according to diagnosis programs stored in the ROM 14 or the RAM 15. Thereby, even if the processing execution starting programs cannot be read out from the hard disk due to abnormal completion of the program starting preprocessing, the diagnosis starting programs are surely started using the ROM 14 or the RAM 15, and then diagnosis processing can be executed according to the diagnosis programs. Thus, information processing apparatuses can be almost surely diagnosed.