Ive had this problem before with the blue light flashing and my compressor wouldnt turn.This a/c system knows when freon pressure it too and when this happens the compressor doesnt work.Even after i refilled it up the light would still flash but the compressor would work and blow out cold air.The next morning i saw freon on the floor and noticed it was leaking from the condenser.Dont know if this is your problem but changing the condenser and refilling the freon solved this issue.