Media quality can be a very big factor with PS2 playback problems. Are they just not playing at all or just skipping and freezing? If its the later then try better media. I always use Taiyo Yuden discs. I had problems with movies with the PS2 until i changed media (originally changed to ritek dye discs until they began to degrade so swapped to TY and haven't looked back since)
If you can give a few more details of the problems you are having then i may be able to help