Try cleaning it with a disk cleaner, sometimes they just accumulate dust and can no longer read the disk.
If that doesn't work and if it is still in warranty sen it off to be fixed.(It should be cheaper than a new one)
If the cleaner doesn't work and not willing to pay to get it fixed, then you could attempt to correct the laser strength yourself (warning this will void your warranty if it still has one, because it requires you to open the ps2) try looking on Google to find a guide.
Bosnoff, June 2007
