please someone help!
I assume these are booting into graphical mode? Have you tried booting into text mode? With the F11 DVD, when the boot prompt first comes up, hit the <Tab> key and add " text" to the end of the line. Then hit [Enter] to boot. At least I can do this with the regular F10 Install DVD, not sure if the Live CD is different...
Also, can you get into a Virtual Terminal? You do that by hitting Ctrl-Alt-F2, Ctrl-Alt-F3, Ctrl-Alt-F4, etc. Maybe there is something more indicative of the problem there.