Imaging killing hard drives

Hello all: I am re-imaging a bunch of older HP
workstations, about 6.5 years old. They work fine for our
purposes so why get rid of them right. OK, so I have
re-imaged 7 of these and of those, 3 would not boot
afterwards. I replaced the HDs on the first two which fixed
the problem.

Today I just saw the third drive die. Now I am suspicious
as it is hard to believe that I could get three failures
within 5 days, even with 6.5 year old drives. Is the
re-imaging simply stressing these drives to the point of
failure?? Or could there be something "wrong" with the
image I am using?? (I did make a new image after the first
failure to see if the image had a problem.)

We run ZfD7 (no field patches) running of OES/NW 6.5sp2.
The image is a standard W2K installation with our standard
suite of software.

All help greatly appreciated, Chris.