Hello guys, just a quick question

Mumsie's Punto head gasket went yesterday So, i got down to fixing it.. The problem is, when it went, it decided to go into 'limp-mode'.When i replaced the gasket the engine management light and the tempature light remained on, I've Took off the battery terminal off in hope the ECU reseting after a few hours. Just wondering if this will work, and what's the proper way to reset the ECU?

P.s. Haven't got the red key

that is the way to reset it did you do gasket proppa, new bolts ?

Cheers big ears