For the scratching sound it made. i could say that it is the guide rail for the lens. Open up your PS2. Remove the top tray with the magnet. Eject the Disc Tray. Unscrew the two screws at the end of the 2 rails. Then use cooking oil to lubricate it. Then put it back again, and you'll have solved your scratching problem. It sometimes happens when you turn on the machine. While you're there, perhaps you can clean your lens using some cotton bud with some soft cleaning material. it will prevent disc read errors.

I have had my ps2 for more than 5 years. And currently it is starting to give me problems. I've done most of the earlier stuffs. The only thing i haven't do is to clean the 2nd lens which is below the visible lens. That is pretty difficult. If that didn't solve the problem, I more or less will say that my lens has worn off and perhaps a replacement would be needed. For replacement, there are a lot of sellers online who can supply such lens. It cost roughly RM200-300, so, be prepared to spend. Alternatively, get a new slim unit.

Cheers.