Используйте GetKeyState.
state := GetKeyState("Capslock", "T") ; True if CapsLock is ON, false otherwise.
state := GetKeyState("CapsLock", "T")
if state
MsgBox CapsLock is Enabled
else
MsgBox CapsLock is Disabled
Используйте GetKeyState
if GetKeyState("Capslock", "T")
;do something because Caps Lock is on
else
;Caps Lock is off
return