单项选择题 A user explains that after the office was vacuumed the previous night their sound is not working and they cannot get onto the network. The user has verified that all of the PC’s cables are plugged into their respective ports. Which of the following is the MOST likely cause?（）

单项选择题 Which of the following describes the random access memory limitations with Vista 64-bit operating system?（）

单项选择题 A user wants to install an external hard drive using the fastest connection available. Which of the following should the technician recommend?（）