Is this really the complete error message? When you press the RETURN key you should be in single user mode using the shell /bin/sh. If this does not work use /rescue/sh instead. I have not had to use any of the files in /rescue. This is just what I would do in your situation. Then please check the files in /var/log for details about the error. Doing a file system check and verifying the health of the disks can be the next steps. This will not solve the problem itself but in my opinion it should lead to a path to collect more information./bin/sh on /etc/rc terminated abnormally, going to single user mode
Enter full pathname of shell or RETURN for /bin/sh:
Indeed, we get frequent power failures here and one machine used to show the above error all the time. I got used to just hitting enter and then typingFrequently it is because the system lost power and the filesystem needs to be checked with fsck(8).
fsck -y.