单项选择题 A technician is troubleshooting a monitor displaying a blank screen and the power indicator light ison. Which of the following should the technician do next?（）

单项选择题 A user states that their work PC has become infected with a virus. Which of the following shouldthe technician do FIRST?（）

单项选择题 A user has recently added a second IDE CD-RW drive to a machine in addition to the primary DVD-ROM drive. The drive opens and closes; however, they do not see it show up in Windows. Which of the following is the MOST likely cause?（）