The easiest way to reset dashboard lights - which are prompted to appear by your car's ECU (its central computer system) - is by disconnecting the battery. So, pop open the hood, and remove the negative terminal of your car's 12V battery. Now deprived of a power source, leave it be for 10 minutes. This should be more than enough time for the ECU to be drained of any residual power, thus resetting it completely. Finally, reconnect the negative battery terminal, and turn your ignition on again. It'll help to take your car out for a short test drive afterward. Last, but not least, check to see if any warning lights (such as the check engine light) are lighting up again after the reset.