Ctrl+Ctrl, Alt+Alt and Shift+Shift???

[Pashers]

Why is it, when things appear to be 'playing up'. Pressing the shift, alt and ctrl keys in pairs fixes a number of peculiar problems!? Had a teacher come in with a laptop. When trying to type in the username and password (on the locked screen), it went funny. The back space displayed boxes. Didn't type anything apart from space. Sometimes moved the text to the right hand side of the text box.

 

Managed to get a USB keyboard (there wasn't a right ctrl button) and then press the wonderful buttons. It worked fine! Does it clean the keyboard buffer or something?!

[Pyroman]

never heared of this fix

[powdarrmonkey]

When you press a control key (actually any key) Windows gets two messages: one for down, and one for up. If for some reason it doesn't get the up message, it thinks the key is still down and interprets other keys appropriately. The black boxes you see are when it tries to display a character that's not in the ASCII set, because its a control combination. Pressing and releasing the 'stuck' key makes sure Windows gets an up message and releases the key in its head.

[Pashers]

It all makes sense now! Thanks.

[Ric_]

Sounds like a Mac fix really... like the trusty unplug from the mains for 30 seconds (no more, no less) and then power up the machine again!