
So, to send Ctrl+ Alt+ Del to a remote machine, simply use the OSK to send Ctrl+ Alt+ End from the session just before the remote machine you are trying to send it to. If I try to use the On-Screen Keyboard to send Ctrl+ Alt+ Del on ANY of those three machines, it refers me to the Start menu, which does not help me at all.

If I want to send Ctrl+ Alt+ Del to Computer C, I open the On-Screen Keyboard on Computer B and use it to type Ctrl+ Alt+ End, which sends Ctrl+ Alt+ Del to Computer C If I want to send Ctrl+ Alt+ Del to Computer B, I type Ctrl+ Alt+ End from Computer A If I want to send Ctrl+ Alt+ Del to Computer A, I type Ctrl+ Alt+ Del from Computer A Here's the scenario: I RDP from Computer A to Computer B and from Computer B to Computer C. Keep in mind that my environment is primarily Windows 7 and Server 2008 R2. That's just how I prefer to work, especially with lots of VMs. For instance, in pre-boot environment or in DOS, Windows 3.0 and earlier versions of Windows or OS/2, the key combination reboots the computer.

The function of the key combination differs depending on the context but it generally interrupts or facilitates interrupting a function. I frequently work with nested RDP sessions that go in several levels deep. Control-Alt-Delete is a computer keyboard command on IBM PC compatible computers, invoked by pressing the Delete key while holding the Control and Alt keys: Ctrl+Alt+Delete.
