How do i remove the redhat linux enterprise 5. No other os in my computer.I am using only redhat linux.?

If you have no other OS on your computer, then removing Red Hat Linux will make your computer inoperable. Is that what you want, and if so, why? Please let me know and I'll try to be more helpful.

Well, if you simply want to delete it, and everything on the harddrive, you can either use windoze (which I assume you want to use) to format the drive, or you can use the redhat installer - go through the installation up to the point where you can delete all of the partitions, delete them, and kill the program.

Another satisfied Linux Jumper?

I have been using Ubuntu (and other distros for 4+ years) and prefer it to windoze.

It depends on what you want to do, but in general speaking, in order to remove an existing OS from your computer, you'll have to use some tools which probably rely on other OSes. However, you always have an option to format the hard drive if your BIOS provides that function... well, that's the case only if you don't care losing all the data.