Hi & Welcome to Linux Questions.-
RHEL
is a server class operating system for the enterprise and it is a 'paid for subscription' through Red Hat.
Are you sure that you want to pay for an os?
https://access.redhat.com/support/
May I suggest to run CentOS which is the rebuild/free version of RHEL.
https://www.centos.org/
http://wiki.centos.org/HowTos/InstallFromUSBkey
Since ISO2USB didn't work for you I'd give UNetbootin a try. Or try Rufus:-
Other members may have other suggestions.
http://unetbootin.sourceforge.net/
http://rufus.akeo.ie/
-::-
*You may also want to include system information and specifications about your computers architecture so others know what they are working with in order to help you.*-::-