"Homer J Simpson" wrote in message
news:JCIUg.50909$E67.45445@clgrps13...

One notorious 10 Mb hard drive Radio Shack sold would only start after a
weekend if you first dropped it about a foot onto a desk!

I've seen many, many drives like that- it's called 'stiction'. The heads and
platters are so perfectly formed and smooth that they can bond together
preventing the drive motor spinning up the platters. Usually the motor can
be heard pulsing and giving up after a few tries. The best way to release
the heads from the platters is IME to hold the drive and quickly flick it in
a rotational plane to spin the internal platters breaking the bond. Freezing
the drive overnight can also do the trick, but the drive must be put in a
completely sealed bag beforehand. Warming with a hairdryer can also help.
Thumping the drive onto a hard surface should be a last resort.

Stiction is not usually an issue on modern drives, but it was common on the
old MFM/RLL/ESDI style drives.

Dave