My computer is running DOS 6.22. I was messing around and deleted the COMMAND.COM file on drive C. As a result, after working normally for about half a minute, an English prompt popped up, and then it just hung. It seemed like it couldn't find the COMMAND.COM file.
I rebooted the computer with the keyboard, and unexpectedly it could still be used normally, except that when I checked with the SET command it had become COMSPEC=C\DOS\COMMAND.COM. I did CD DOS, and sure enough there was a COMMAND.COM file in the DOS directory.
I used UNDELETE to restore the deleted COMMAND.COM file in the root of C and rebooted, but it was still COMSPEC=C\DOS\COMMAND.COM. So I checked CONFIG.SYS and AUTOEXEC.BAT separately, but couldn't find SHELL or COMSPEC.
I'm really puzzled. Since SHELL and COMSPEC weren't used, how did the computer end up with COMSPEC=C\DOS\COMMAND.COM? Could it be that MSDOS.SYS or IO.SYS was modified?
I rebooted the computer with the keyboard, and unexpectedly it could still be used normally, except that when I checked with the SET command it had become COMSPEC=C\DOS\COMMAND.COM. I did CD DOS, and sure enough there was a COMMAND.COM file in the DOS directory.
I used UNDELETE to restore the deleted COMMAND.COM file in the root of C and rebooted, but it was still COMSPEC=C\DOS\COMMAND.COM. So I checked CONFIG.SYS and AUTOEXEC.BAT separately, but couldn't find SHELL or COMSPEC.
I'm really puzzled. Since SHELL and COMSPEC weren't used, how did the computer end up with COMSPEC=C\DOS\COMMAND.COM? Could it be that MSDOS.SYS or IO.SYS was modified?