Tried everything – how do I unlock my keyboard?

My laptop (HP Pavilion) was in standby mode for about two days, and now the keyboard no longer works. There's no F key with a keyboard or lock symbol, but I've pressed all of them, including in combination with fn, just to be on the safe side. There's no keystroke delay. I've looked for new drivers and even disabled them and restarted. Pressing the Shift and arrow keys for 8 seconds each didn't work either. Does anyone have any other ideas?