Which of the following BEST describes the main function of a web server?

Upon booting a workstation, a technician hears a distinct clicking sound after power is applied to the motherboard. Which of the following would MOST likely be the cause?

A laptop has been returned for a screen repair. The owner insists the screen is broken, but occasionally a faded image is able to be seen in very bright settings on the desktop. Which of the following steps should the repair technician take FIRST?

A user's mobile phone gets really hot to the touch and does not retain a charge. The user also reports that the phone is very slow, especially while charging. Which of the following is MOST likely causing these symptoms?

A technician powers on a PC and its monitor and sees the following error message:
No input signal detected
The display lights on the computer are on. Which of the following is a possible solution?