单项选择题 A new processor was recently installed on a one year old motherboard, replacing the original processor. The processor is on the motherboard’s supported processor list and was double checked for proper installation. However, the PC refuses to POST properly and displays no video onscreen. Which of the following is the MOST likely issue?（）

单项选择题 A user states that the LCD display on their laptop has intermittent lines on the screen. The technician notices that when the display panel is moved, the line appears and then disappears. Which of the following is the MOST likely cause?（）

单项选择题 A user needs a laptop keyboard replaced because the space bar is not working. Mike, a technician, replaces the keyboard, and notices that a diagonal set of keys will not respond. Which of the following is the MOST likely cause?（）