单项选择题 A technician is booting up a computer but the computer never moves beyond POST. The floppydisk drive light stays lit continuously during the boot process. Which of the following is the MOST likely cause?（）

单项选择题 A program configuration file on a shared computer changes each time the program is run, causing the program to fail. Which of the following steps could a technician take to help prevent this file from being changed?（）

单项选择题 A user installed a Blu-Ray drive in their PC. The user reports that the new drive and their existing DVD-RW drive are not operating. Which of the following needs to be replaced?（）