hello everybody,
i use rhel 4. when uninstallimg nero i used the command rm -rf /usr/bin/nero/
after restarting the system, it shows no inittab found. enter runlevel. how to bring back the system up and running ?
please help.

I would be willing to bet that you made a typo and entered something like "rm -f / usr/bin/nero/" wiping out the entire root partition.

How did you install nero? /usr/bin/nero/ sounds odd and very non-standard. Having a /usr/bin/nero program would be what one would expect.
If you installed from rpm, then use your package system to uninstall. You can also use the rpm command: "sudo rpm -e nero".
If you compile a package from source using "./configure && make && sudo make install", then you can run "sudo make uninstall" to
uninstall the package. For other packages with custom installers, refer to their documentation for instructions on uninstalling.
They may have an uninstall program installed along with the program.