This is quite an easy question. PS2 games are organised on the DVD disc by something called an LBA. These are special locations on the disc. Data is stored about half an inch from the centre of the disc to make it easy and quick for the laser to collect the data from a disc. It also puts less strain on the laser arm and its mechanics. The problem you are experiencing is subject to how a copied CD (CDRs are prone to this problem) is put together. If you copy a DVD to a DVD-R the data is stored on the same part and place on the disc as the original disc. This sounds and functions like a normal disc. CDRs (which is what you are probably using by the sounds of your problem, sorry if it isn't) are ripped from the DVD's and burned onto a CD. CD's are smaller than DVD's so the data is not in the same part or place on the disc, instead it is put randomly on the disc. What your PS2 is doing is searching the disc for the data. The grinding noise you are hearing is the sound of the laser arm searching for the data on the disc. This does wear your laser prematurely but there is not a lot of difference in the working time of your laser before it wears out, providing you don't go and play on the game 12 hours a day every day. If this is not the case then it won't cause any damage. Some games are very noisy like this, another game is GTA3 which is an extraordinarily noisy game. Some games such as State Of Emergency which fit onto a blank CDR work and function like the normal game because it doesn't exceed 700MB on the original DVD game. If you are not happy with the sound, then get your laser recalibarated and aligned. This can help your PS2 read the discs quieter and it will further reduce the damage that will be caused.
I hope this helps you. Your question should have been answered as fully as possible. If you are unsure about anything else then just go to my profile and e-mail me from the link there.
LUFCfan
