vertical line on imac G5 screen

that should be a big enough defect that apple should replace your unit with a working one.

I agree that it definitely sounds like a hardware problem and would be covered by the warranty.

However it is very unlikely Apple will replace the whole unit, after the initial DOA period (I think its 4 weeks with Apple) the computer will get fixed and not replaced.

Had one on my 23 inch display

Only showed up on white and some colors of yellow.

Just bring your mac to an apple store and show it too them.

I got mine fixed in just a few days.