Send Ctrl+Alt+Del command of Remote Desktop Viewer does not work in Windows Vista/7

In order to allow "virtual" pressing Ctrl+Alt+Delete key combination remotely, Windows Vista/2008/7 require setting up special policy in Active Directory Group Policies or Local Group Policies.

In addition, Net Control 2 version 8.11 or higher is required to generate this sequence remotely.

To change Active Directory Group Policies, please open respective command in Start menu. If your network does not have a domain and Active Directory services installed, you need to modify the policy on each user computer:
- press Win+R key combination;
- in Run dialog type:
gpedit.msc
- click OK.

In Group Policy Editor:
-  at left pane please find Computer Configuration -> Administrative Templates -> Windows Components -> Windows Logon Options category;
- at right pane, please double-click "Disable or enable software Secure Attention Sequence" policy, and set it as "Enabled";
- set additional option to "Services" or "Services and Ease of Access Applications"
- click OK