The light coming on means there's a serious problem with your car's oil system. Ignoring it could lead to catastrophic engine damage.
Here's what you should do:
1. Check the oil level immediately. Use the dipstick. If the oil is low, add the correct type and amount of oil (check your owner's manual).
2. If the oil level is low, don't just drive the car. Figure out why it's low (leak, etc.). Continuing to drive with low oil will severely damage your engine.
3. If the oil level is fine, the problem is likely with the oil pressure itself. This could be due to a failing oil pump, worn bearings, or other serious engine issues. Have the car towed to a mechanic immediately. Do not drive the car.
4. Once the underlying problem is fixed by a mechanic, the "check oil" light should go out. You don't have to reset it; it's simply an indicator of a problem that's been resolved.
In short: Don't focus on resetting the light; focus on fixing the serious problem causing the light to come on.
