单项选择题 A user states that they unplugged their mouse to clean the roller ball, but after plugging it back in the mouse no longer functions. Which of the following is the MOST likely cause of this issue?（）

单项选择题 Which of the following utilities would be used to configure energy saving measures when a laptop switches to battery power?（）

单项选择题 On a Windows XP machine, which of the following settings should be configured to allow draggingof files without holding the mouse button?（）