I have the exact problem: turn xbox on, no vid+no sound+cant eject.
When i turn on my modchip (by holding my power button, thats how my modchip turns on) everything boots up fine.
Sometimes it will boot up without the mod when i need to use live but most times it just give the the no vid+no sound+cant eject problem.
Is there anyway to fix this problem?? (eg flash bios, etc)
My chip is the Aladdin chip, dont know the version. I have one of the earlier v1.0 or v1.1 xbox.