Can't Start MS-DOS 5.0 or later on a BSR Computer (74551)

The information in this article applies to:
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q74551


After installing MS-DOS or later on a BSR computer, you may be unable to start MS-DOS from the hard drive, Uninstall disk, or a MS-DOS 5.0 or later bootable floppy.


The BIOS chips in some BSR 386 machines prevent MS-DOS from properly completing its starting sequence.


If you are having difficulty starting MS-DOS 5.0, 6.0, or 6.2 on a BSR machine, turn off switch 2 on switch bank 1 of the system. If the machine still does not start, contact BSR for a BIOS upgrade.

NOTE: Quarterdeck Expanded Memory Manager (QEMM) does not work on the machine after this switch has been changed.


If you want to uninstall MS-DOS 5.0, 6.0, or 6.2, you must start from a floppy disk from your previous version of MS-DOS, back up the hard drive to floppy disks, and manually install the previous version of MS-DOS to the hard drive. To reinstall your previous version of MS-DOS, do the following:

    Use the Sys command to transfer the previous version of DOS system files to the hard drive.
    Copy the COMMAND.COM file to the root directory of drive C.
    Copy the contents of the previous version of MS-DOS disks to the DOS directory.
    Find the old AUTOEXEC.BAT and CONFIG.SYS files on the Uninstall disk as AUTOEXEC.DAT and CONFIG.DAT. Copy them to the hard drive, and rename them AUTOEXEC.BAT and CONFIG.SYS.
For more information, contact DAK Industries technical support.

The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Modification Type: Major Last Reviewed: 5/12/2003
Keywords: KB74551