Stuart Allman wrote:
>
> Whenever I read the program memory of my 16C57, every location is 004
> (after erasing).  Does this mean that the PIC is shot?  I've been using it
> for quite a few weeks now, without any difficulty, but now it refuses to

<snip>

A couple of days ago John Barrowman of Parallax informed me that the
latest PIC windowed devices being shipped by Microchip incorporate
a code protect fuse that is NOT erasable. Perhaps this is your problem?

                Bill