Some discs don't load

[mike_sheree]

I have some discs that refuse to load. After spinning for a bit, it goes back to the dreamcast menu. Soul calibur, Who wants to be a Millionaire, Sega Bass just to name a few. Most other games work fine. Oh and Shenmue gets to certain points in the game and the screen blacks until I turn it off
Can anyone help?

[TeamXlink]

Are there any scratch's in the discs?

I've noticed Dreamcasts, seem to be more picky with GD-Roms.