Hey drop4205. Even though the disk is nominally "idle" in fact the PC is never truly doing nothing. It is constantly running bits and pieces in the background, antivirus, windows services and on and on and if the disk is "idle" it may start TRIM or garbage cleaning and all this will mean the OS is going to access the disk and the light will blink.

It may also have become sentient and be plotting to kill you but my psychologist advised me not to talk about this in public again so.......

Do you have AI Suite II installed? That will buzz the hdd every second. Also other monitoring type softwares will do the same. That's how you get the constant temps/stats etc.