Abs fault

Hi

Laguna 1.9 dci 05 plate

I have changed the nsf wheel bearing and now have a abs light on, everything has gone back as it came off.

Do i need to reset the computer to get rid of the light or will it just go off when i find and cure the problem.

I replaced the nsr caliper and bleed the brakes but the brake pedal now goes slowly to the floor there are no leaks.

Is there a sequence to bleeding the brakes as am putting another master cyl on as i think thats the problem.

Thank you