单项选择题 A user wants to install a new game and needs to make sure the proper version of DirectX isinstalled. Which of the following is the BEST way to check for the DirectX version?（）

单项选择题 A technician installs a new video card in a desktop with onboard video. The technician boots the unit but sees no display. The monitor power light is on and the OS seems to be loading. Which ofthe following is the MOST likely cause?（）

单项选择题 A technician just installed an antivirus suite on a workstation. It is kept up-to-date and has recently scanned the system. A day later the user reports slower response times than usual. Which of the following is the user MOST likely experiencing?（）