ok got a problem bought an old 1.25 zetec fiesta all seemed to be ok with it

however - engine warning light is on after i got to work today, oil level was low (i never checked it to be honest) but its running ok no knocks etc, no misfire and oil level has been topped up.

How do I go about resetting the engine warning light? I have remvoed the negative lead and will put it back on for my journey home but not sure if this will work or not?

the car was stood for 8 weeks without use and is coming up for 15 years old so i expected some issue not right away!