单项选择题 A technician is testing a power supply for correct output voltages at the HDD power connector. Which of the following voltages should the technician expect for a correctly working power supply?（）

单项选择题 A customer reports that error messages occasionally appear and quickly disappear. Which of thefollowing is the BEST place for a technician to begin troubleshooting this issue?（）

单项选择题 A user, Jill, is reporting her mouse is moving when Jill is not moving it, and the computer is running slower than normal. Which of the following is the FIRST action that Karen, a technician, should take?（）