🚀 go-pugleaf

A question for all you hard disk mavens:

I've got a Bleeding Edge Model D 4.77 MHZ PC, with
a 30 mb hard drive.  I've noticed something fairly
peculiar as follows:

When "cold" e.g. freshly booted, I can access the hard
drive no problem.  After about 5 minutes or so, I begin
to get seek errors.  No matter what I do, I can't get at 
the damn drive.  Running 'fdisk' off drive A, I am
told that the FAT is gone and that there is no partition
on C.  Of course, this is not the case.  If I power off
the PC and *immediately* turn it back on, drive C is
still unavailable.  If I wait an hour or so, and then power
up, the problem repeats itself as originally stated, e.g.
5 minutes of pleasure followed by infinite pain.

Does anyone have an idea about what this could be?  I can
use the PC basically as a one floppy machine right now.
I'd like to have the hard disk back.

Thanks to any and all who reply.

Rob