Hello I know that clicks & funny hard disk noise is rather common and mostly to do with the sudden motion sensor. My 13" MBP 5,5 though recently has developed a very scary new sound: 1) similar click noise to the sudden motion sensor sound, but MUCH louder. 2) Ticks or tings in random intervals. Almost like pinging a glass*. *NO, it's not the system sound! The funny thing is that these sounds and clicks occur in random intervals while the laptop is in clamshell mode attached to an external screen - the laptop is completely flat and on the desk. No vibrations or anything else. I have just finished backed all my data with time machine. Just wanted to see if anyone has similar experiences? Should I contact Apple? I got the 3 year warranty. Thanks! EDIT: It's the 160GB Hitachi model.