Windows Vista heuristically detects installation programs and requests administrator credentials or approval from the administrator user in order to run with access privileges. So applications called ''setup.exe'' and ''install.exe'' will prompt for administrator credentials (if running as standard user) or approval (if running as administrator). ...

This should be easier to find, and I'll happily be told how to get to it normally... But if you search Windows Help for ''ctrl-alt-del'', you'll get a link to a page which takes you to a dialog box that lets you set this option. In the dialog, it's on the Advanced Tab, at the bottom. If you can't find it in the help, you can just run NetplWiz.exe ...