What you likely want to do is one of the following, depending on your problem:
* Reset the ECM: This clears various fault codes and adaptive learning data. The method varies slightly depending on the specific ECM, but the most common way is to disconnect the negative (-) terminal of the battery for at least 30 minutes. This allows the ECM's memory to completely clear. Reconnect the battery and let the car run for a while to relearn driving habits. Caution: This will also reset the radio presets and clock.
* Clear trouble codes: If you have a check engine light or other warning lights, you'll need an OBD-II code reader to read and clear the diagnostic trouble codes (DTCs). Auto parts stores often offer this service for free.
* Reboot the infotainment system (if applicable): If you're having problems with the radio, navigation, or other in-car electronics, these might have a separate reset procedure. Consult your owner's manual for details.
In summary: There's no single "reset computer" button. Disconnecting the battery negative terminal is the closest equivalent to a full reset for the engine control system. If you have a specific problem, providing more detail will help suggest more targeted solutions.