Restoring MS-DOS System Files
The MS-DOS files COMMAND.COM, 1O.SYS, EXTMSDOS.SYS, and MSDOS.SYS
are necessary for the operation of your computer. If any of these files are accidentally
deleted or modified, your computer will not function. This appendix describes the
procedure for restoring these files without affecting the applications and data files that
may be on your hard disk.
If you need more information, see the MS-DOS User's Guide and Reference furnished
with your new computer.
Note: IO.SYS, EXTMSDOS.SYS, and MSDOS.SYS are hidden files. You will not see
these files if you view a directory of drive C using the DIR command.
If COMMAND.COM is Missing
If COMMAND.COM is missing from your hard disk, the screen displays this message
during the boot process:
Bad or missing Command Interpreter
The computer then becomes inactive. Complete the steps in the next section to restore
COMMAND.COM to your hard disk.
If SYS Files are Missing
If the IO.sys, EXTMSDOS.SYS, and/or the MSDOS.SYS files are missing from your hard
disk, the screen displays the following message during the boot process:
Non-System disk or disk error
Replace and press any key when ready
This message is repeated when any key is pressed. Complete the following steps to restore
the SYS files to your hard disk.
E-10 Troubleshooting