If some keyboard key is pressed several times in the short period of time, the accessibility window will appear. It’s possible to disable this behaviour.

Just create the following REG-file and import it with the regedit:

Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Control Panel\Accessibility\StickyKeys] "Flags"="0"

Alternative: just do it from the command line:

REG ADD "HKEY_CURRENT_USER\Control […]