Can a PS3 console 80 gig play PS2 games?

Yes,If it also has 4 USB ports otherwise no it can not. You would never need a Harddrive it was never the harddrive that would allow a PS3 to Play PS2 and instead it was other hardware and software combined. you might need a hard drive, PS3's also play blu-ray discs, they can also play PS1 games