hello evry one ,i have an old powerbook g4 powerpc 10.4 .11 ,recently started having problems with realplayer downloaded videos ,they woulld download from youtube as full mgbytes but the video would only be a few seconds long ,,,others would come up error "not a movie file" this is the only problem i can pinpoint before the laptop got stuck on blue screen at bootup ,i was able to start it in safe mode, ran disk prmissions and repair,,main drive could not mount,,so i ran a repair program,, checked the permissions and verify said all wasfine,,but still no mount point on main drive,,it booted a coupletimesseemed normal,,,and now itjust gets stuck onblue screen ,will not start in safe mode,,,and trying to start up holding "t"(for disk drive boot) gives what looks like a fall out shelter logo that bounces round the screen ,is there any way anyone knows i can get this system back up ,to try disk utilities again? please help