windows 7 - Occasionally Unresponsive Keyboard and Mouse

Occasionally, my keyboard and mouse suddenly go into some unresponsive state.

Symptoms of this state:

• Seems to occur randomly, sometimes multiple times per day


• Pressing Esc seems to be the only way to exit this unresponsive state.


• There is no audible or on-screen notification of this change


• While in the state, the Caps Lock and Scroll Lock LEDs flash back and forth

I tried disabling all startup programs, but the issue still occurs.

The keyboard and mouse are both generic Dell ones.

What is causing this behavior? Where do I disable it?

Answer

Sounds like a KVM Switch programmable mode, rather than a bug. It looks like on some packages, the control key is an alternate mode-switching key and a double-tap (a common occurrence) puts you in programmable mode.

I am reminded of the Windows sequence of 5 rapid taps of the shift key putting you in Accessible mode. Many people would inadvertently enable Sticky Keys while playing FPS games.

From a random IOGEAR KVM Switch manual:

By default, all of the following commands begin by pressing the [Scroll Lock] key twice. A few PC key - boards and all Apple keyboards do not have a [Scroll Lock] key. If you have one of these keyboards you must use the alternate toggle key of [Control] instead. [...]

You may enter advanced hotkey mode by pressing and holding [Num Lock] on the number pad, then pressing the [-] key on the number pad and immediately releasing both keys. [...] If you have done this correctly the Caps Lock and Scroll Lock lights on the keyboard should begin flashing. This means you are in hotkey mode, which will be shortened to just [HKM] below. If you are having trouble entering hotkey mode press [Esc] and try again.