Will not read the disc

If you used to play those discs before and then suddenly it stops reading, then you might need to clean your lens that reads the disc.

Do you have a cd cleaner? Go and insert it and play for 30 seconds. It this still does not work, you can open your ps2 cover and manually clean the lens with a soft ear bud damped in an alcohol and gently wipe the lens surface. Also if you have a blower, you can blow those dust off.