lol well the laser unit it mounted on 2 metal rods, it glides up and down on them.
on the one of those metal rods the laser is attched and the other one it just rests on it, on the side that it's attached to, remove the little black screw that holds the rod on place, you can now tilt the rod up and slide the laser unit off the rod.
now there are 2 screws on the laser unit, one for the dc lense and one for the dvd lens. these are what you use to adjust the power of the laser. they must me turned a tiny amount each time then tested. ideally you need an ocillyscope to check the power output of the laser, but you can make it stronger without it.
PLEASE NOTE: if you turn the screw to much, you will kill the laser completely.
it depends on what version ps2 you have, on the positioning of the 2 screws you need to adjust. heres a sample pic, so you know what your looking for -
this might not be completely accurate
make sure to turn the screw as little as possible each time ( a couple of degrees )
there is no guarantee that this will work either, without the specific tool, you are adjusting it totally blind. and there is a good chance the laser is dead anyway or you could kill it if you over adjust.
mark the screws starting position and don't go beyond about a quarter of a turn in total
hope that all makes sense, it's been agaes since ive been inside a ps2, so some of the details are a little fuzzy.
have a google theres loads of info on it out there
good luck !