After read some threads regarding to people's new imac with yellow tint/ buzz noise/and other issues related to the screen. i decide to unboxing imac in APPLE STORE and give it a test to make sure i do not bring issues home. i understand most imacs are free of issues, what i read here is just a small group of people. but after had 2 faulty Alienware laptops returned to DELL, i have to be careful to any computer manufacturer. However, as a newbie, i have no idea what should i do to test it in APPLE STORE. So any ideas?