Ok.... i have to run out quick, but i figured i'd post this real quick and see if anyone knows what might be causing this. I recently purchased a Samsung Spinpoint 250GB SATA2 hard drive to go along with my old WD 160GB hard drive. with both hard drives in my computer, i get an audible vibration noise that i can even feel on my case. with just the WD in, i get no such vibration. haven't tried with just the Samsung in yet, but i'll probably do that later. Think i got the same vibration when i had bought a Seagate drive of the same size and type..... and i think the vibration might have disappeared when i used only that drive. i'll be back in a little while. hopefully you guys will have some helpful tips/suggestions.