Have installed 10.6 with USB stick. OS X won't load - just stuck on splash screen with no dock and no menu bar.
Forced close and pressed F2 on restart to use USB stick to reinstall OS. Now most BIOS options are greyed out with USB legacy support disabled, so no go there.
Have made killcmos.iso disk (have used this before to clear options being greyed out) but can't boot from it because can't change Boot Option either.
All that now happens is the OS X screen not loading.
Hoping someone can help....