单项选择题 Computers on the network are frequently infected with viruses, malware, worms and Trojans.Which of the following should Mike, a technician, update automatically to prevent future problems?（）

多项选择题 A printer is consistently printing random characters on every page. Which of the following should be done? （）(Select TWO).

单项选择题 A HDD is almost full and constantly reads and writes data. Which of the following tools may repair files on the HDD?（）