i've never owned an iMac, is it normal for the dvd drive to be really loud when the dvd/cd spins? there's a lot of vibration and when i tried using my friend's imac, it spins very quietly....does anyone have this problem also? since i bought this imac on the online apple store, can i just bring it to an authorized apple reseller to have it fixed for free since its still under warranty? or do i have to send it back to apple for them to fix it? thanks a lot!