Actually your PS2 won't play CD-ROMS (Some PS2 Games are on CD's there have blue bottoms) this is actually a common problem that happens because the laser for your CD-Rom reader has been knocked out of alignment. Any Gold bottom PS2 game should still work. You should contact sony to see if they still offer free repairs.
you most likely have a wrong region code games. there's europe region games and north america region games. If ALL of your games doesn't work, you obviously have a broken PS2. try cleaning the lenses before.