单项选择题 Youhave30NT4.0machinesand5W2kPromachinesonyournetwork.YouwanttosharefilesontheW2kPromachinesthatonlytheycanaccess.TheNT4machinesmustnotbeabletoaccessthosesharedfilesatall？（）

单项选择题 You are responsible for migrating client computers from Windows 98 and Windows NT Workstation 4.0 to Windows 2000 Professional. You have installed Windows 2000 Professional and reinstalled the necessary application on 10 computers. You have returned these computers to their users. The users of these computers report that their word processing application will not start. What should you do?（）

单项选择题 Duringstartup，aWindows2000ProfessionalcomputerinyourofficeproceedsdirectlytothedesktopwithoutfirstpromptingforausernameandpasswordfirstYouneedtoenforcelogonrequirements.Whatshouldyoudo？（）