Does the Hard Drive access ever stop in Vista?

I have applied all of the usual ways to stop disk thrashing. However, the
disk is still be accessed almost exactly once per second.

This would not bother me, but the light on this HP computer is right under
the left side of the screen...and anything flashing in visual range is
annoying.

XP does not have this regular access behavior and goes dark for long periods
on a similar laptop.

Comments or solutions appreciated...