I think I know what going on.
Looks like you have HD and after the boot, the screen is "screwed", but when you skip the startup-sequence the screen is fine.
It looks like the monitor preferences are set to display other then PAL/NTSC, and could be VGA or DoubleNTSC or DoulblePAL.
So to fix it, select boot with no startup-sequence
in CLI type LOADWB
When it loads, and it may give you errors, just ignore them, go to the boot HD and Prefs folder, select ScreenMode, and then select NTSC. Save and reboot.