[Headly]

Have you tested PS1 CD-R's? These are more easily readable by the laser, if it boots cd-r ok then it is probably the laser. What version do you have? Older versions have weak lasers. If all else fails open PS2 and check wires again. It isn't rare that wires fall off during reassembly. If a wire fell off from the sound of it I would suspect the power wire. It is difficult to get a good connection on it.