Have you checked for a virus?

regardless...

Boot from the NetBSD 1.0 floppy(s) (don't install!).
cd /usr/mdec
disklabel -B -s bootsd /dev/sd0a
reboot

removed diskette, boot off hard drive and all is well!

(substitute wd0a for sd0a if you are using a IDE)

jam
**********************************************************************
*       John A. Maier          * Research Assistant For Datastorm    *
* E-mail: johnam@datastorm.com * Technologies Inc. (Procomm Plus)    *
*                              * (314) 443-3283                      *
**********************************************************************

 ----------
From: owner-port-i386
To: port-i386
Subject: Disklabel trashed....
Date: Saturday, May 20, 1995 9:33PM

Hi,

This morning I tried to boot NetBSD (March current) from my hard drive (I 
use
OS-BS), and I got the error message "No Operating System".  I then booted of
my kernel floppy, and found I couldn't mount my hard drive because of a
"Bad Super-Block".  "Disklabel" displayed only two disk partitions, 'a' and
'd' and displayed other errors......

I have my disk split between NetBSD and MS-DOS.  In the past week I'd been
working with Photoshop pretty intensively, and for the first time on this
disk, used almost all the MS-DOS partition disk space.

Questions:
1)  Where is the disklabel written to disk?
2)  Is it possible that the disklabel was written in the MS-DOS partition,
    and was overwritten once the MS-DOS partition filled up?
3)  What can I do to prevent this problem in the future?
4)  I remember the Free BSD FAQ mentioned something about leaving some
    unallocated disk space outside of the BSD and MS-DOS partitions.  Is
    this necessary?  How many tracks should be left free?

Thanks for any help,

        Chris Perleberg