do i need to upgrade my ps2 firmware to be able to play new release games today? and how will i upgrade my firmware????

and i have one another question... why some of my games doesnt work when i open my ps2 with the disc inside the screen always black??? do you guyz think that my lens has the problem or my disc has the problem because not all my disc are not working only some are not working??? and if my lens has the problem how will i fix it???? how will i clean it???? my ps2 is the old one the big one not the slim one