ARCHIVED: When I boot my Windows computer, why do I get a "Missing Command Interpreter" message?

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Several situations can cause a "Missing Command Interpreter" message when you boot your Windows computer. In order of likelihood, they are:

You have a non-bootable floppy disk in drive A: of your computer: Remove any floppy disks and press Reset or Ctrl-Alt-Del. Be careful about having floppies in the drive when you start your computer; this is how boot sector viruses are transmitted.
The COMMAND.COM file has been deleted from the root directory of your hard disk: Boot up with a bootable floppy of the same version of DOS, and copy the COMMAND.COM file to your C: drive. Alternatively, boot with any version of DOS above 3.3 and use an UNERASE or UNDELETE program if you have one. (DOS 6.0 and higher come with UNDELETE, while Norton Utilities has UNERASE.) You might also boot and then copy the COMMAND.COM file from your DOS subdirectory (usually \DOS, or \BIN for Zenith computers) to your root directory.
Note: If running the dir c:\ command shows you an empty directory, you may have accidentally deleted all the files in your root directory. It is fairly common for users to issue the del *.* command in the root directory, mistakenly believing they are in a subdirectory. In this case, not only is COMMAND.COM deleted, but also AUTOEXEC.BAT and CONFIG.SYS (two important files which determine how the computer operates after booting). If this has happened, using an UNDELETE program is the best option.
The directory structure or FAT (file allocation table) of your hard disk may have been damaged: Boot some version of DOS from a floppy disk and run the dir c:\ command. If this command does not succeed, a disk checking program like NDD (Norton Disk Doctor), PCTools, or DOS 6.2 and above's ScanDisk can determine whether logical damage has occurred to the drive. You may want the help of a computer technician, as these disk checking and repair programs can do more harm than good if used improperly. Contact your computer's manufacturer. Or, if you are affiliated with Indiana University, you can contact the computing Support Center or Help Desk at your campus. For more information, see the Knowledge Base document Contact your campus IT Support Center
Your hard disk or hard disk controller may have failed: Sometimes a failure of either component is temporary, and resetting or turning the computer off for 15 seconds and then back on will get you going again. However, once your computer is working properly again, make a backup of your files as soon as you can; you may not get a second chance. Drive or controller failures are often signaled by a "1701" error at boot time. After getting a good backup of your drive, sometimes running a disk repair program such as Norton Utilities' CALIBRATE can refresh and strengthen the magnetic signals on the disk, making it usable again.

If you saw this message not at startup but when exiting or shelling out of an application (e.g., /System in Lotus 1-2-3), add the following line to your AUTOEXEC.BAT file:

  set comspec = c:\command.com

This tells DOS where to find COMMAND.COM at all times.

Note: In Windows 95, if you see this error when entering DOS compatibility mode, the file COMMAND.COM must be replaced with the Windows 95 version of COMMAND.COM. The Windows 95 version is 32-bit, and some applications will not run correctly if a DOS version is used in its place. You can find the Windows 95 version on your distribution disk or CD-ROM.