We are purchasing some 21 used HP XP machines that are currently on a domain. I was going to get into them via the "options" dropdown for the individual PC at the Control-Alt-Delete sign-in, but that has been disabled. How can I get into these machines now?

This forum is for exchange related issues. For your issue please use the Windows XP SP3 or Windows Server 2008 Forums which would be the more relevant forums for your question Windows XP SP3: http://forums.microsoft.com/TechNet/ShowForum.aspx?ForumID=2010&SiteID=17 Windows Server 2008: http://forums.microsoft.com/TechNet/default.aspx?ForumGroupID=161&SiteID=17