Webber help me please !

I have problem with my dreamcast. When I put a written cd it make a strange song and it doesn't open. This morning I had play these games and that was working and now it doesn't work.
Tell me how to make it work because All my original games are working or tell me what going wrong with my lens and how to make it work.

[webber]

what games are they and what speed did you burn them at and with what software,

are they self boot or non self boot

regards
webber
you can e-mail me if you want