simple question-how to login as root.

[arda]

sorry for asking such a simple question but I can't login to my newly
installed RedHat box with telnet..

I can login as ordinary users , but the login says "Incorrect Password "
when I try to access the machine from other computers.. I can login when I'm
on the console..  In slackware linux I know the use of hosts.deny or
hosts.allow, but in RedHat linux I couldn't configure it..  Please help..


There's also another question I'd like to ask.  when I login as an ordinary
user and use "su" to be root, that's ok, i can be the root, but I still
can't execute the binaty files under /sbin.   It says "bash: reboot: command
not found".. why is that for? I can copy, delete that file... Even the file
is executable, and i'm the owner,  I still can't execute? why?

Thanks in advance..