Concrete Driveway Sealer Video

i have approx. 5500 sq. ft. of concrete. its about 1 yr old. a sealer was put on it after it was poured, but the surface seems to absorb water. i am considering using a penetrating sealer on it but i am concerned about the original sealer. do i need to make sure the old sealer is off? if so how do i remove it? i have a 2500 psi pressurer washer, will that do the trick? i need your advise. also can you recommend a good sealer? i've seen some that say you only have to apply it 1 time and never again, is this true?
I NEED YOUR ADVISE!!! THANKS, JOHN