I have some problem while installing RHEL 5 in my laptop.

Put the CD in the computer, boot the computer and follow the instructions at the screen. If you have some problems, then use some fix to that problems.

you din't mention your problems.

Ok as said earlier you have not mentioned what problems are you facing while installing it.
But my question would be, do you seriously need RHEL5 ? It is an enterprise level distribution primarily developed for servers in mind. And if you want to install linux on your laptop for your everyday use then you should look for desktop distributions like Ubuntu, Fedora, OpenSuse, Mandriva, Dream Linux etc. etc.
And while the list does not end here you may want to search google a bit or tell us what your primary use would be so that we can help you out.
Also, if you are too adamand on using RHEL5, then there is a suggestion that you use CentOS5 which a clone of RHEL5 with logos removed.

There is absolutely nothing wrong with using RHEL/Centos for a desktop/notebook. There are thousands of businesses out there that do this. If you can afford the RH subscription fee then you can run RHEL. If not, you should be running Centos. Centos is RHEL without the paid support and the logos removed. If you want to run a RH based system with long term support RHEL/Centos is your only real choice.