black screen until X ¿why?

Hi

I'm a linux user from 3.4 version. with this version 5.01 all works fine, but. When I put the cd at cd drive, I see the firts screen (to writte some indications at boot or do nothing), then all is black screen, but is working, at X system is possible see it, and KDE or Window Maker, but if I do ctrl + alt + f2 or f3 or another, to get a TTY is not possible see it, but is there, because i can writte the roo user and root password and do reboot, but only guess, I don see it. ¿any one know why?

that's interesting
I'd say a dodgy VGA card
not working in a particular mode

look for some vga mode cheat codes