A customer reports that their computer is displaying `operating system not found’ while booting. The technician confirms that the computer booted fine the previous day and that no devices were added. The technician also confirms that no software changes were made to the system from the previous day. Which of the following is the problem?
A.
The network cable is unplugged.
B.
A diskette was placed in the disk drive.
C.
The keyboard is unplugged.
D.
The system has been infected with spyware.