单项选择题
A. Turn the case upside down, shake gently and let the screw fall out.
B. Use a shop vacuum to retrieve the screw.
C. Use the hardware abstraction layer (HAL).
D. Use an extension magnet.
单项选择题 A technician is troubleshooting a laptop LCD, and when the cover is opened nothing shows on the screen. Then all of a sudden the screen comes on and works fine. Which of the following should the technician check FIRST?（）
单项选择题 Which of the following commands would be used to verify the integrity of critical system files?（）
单项选择题 Which of the following Microsoft encryption software provides the HIGHEST level of security for PCs running Windows Vista Enterprise or Ultimate Vista?（）