单项选择题 A new floppy drive was just installed into a PC. The drive powers on at system boot but the status LED does not turn off during operation. Which of the following is MOST likely the issue?（）

单项选择题 A user wants to be able to receive help from a coworker that is located outside the company’s local office. Which of the following MUST be enabled to allow the user to watch and interact with the coworker simultaneously?（）

单项选择题 A user replaces a laptop’s wireless PCMCIA card with a different vendor’s card. All of the new card configuration steps have been followed. The OS sees all known wireless networks but cannot connect to the user’s network. Which of the following is the MOST likely reason for this behavior?（）