1. Mouse/keyboard connection to the computer host is faulty.
2. Mouse/Keyboard is not compatible with the computer host.
3. Mouse/Keyboard is faulty.
1. Check the power supply of the printer, the signal cable connection to computer host, and whether the printer is in linked mode.
2. Check installation and setting of the driver for the printer.
3. Check whether the computer is virus affected.
1. Software core file error or missing.
2. Registry is damaged.