Dual boot optation not showing after win XP installation
 

hi, i have first install redhat linux and after that installed win xp pro after complete installation, i am not gating boot option and automatic start win xp by default please help out... and i am unable to boot with Linux..

The mistake you made was installing Windows after Linux. Welcome to the dual-booting paradigm. :)

If you can, somehow, manage to boot into RedHat, you can re-install the bootloader, and all should be good. Your only other choice, in this matter (that I know of) is to just re-install RedHat.

It's just ms's policy: assume that Windows is the only OS you need in your box.

Windows rewrites the boot sector with it's own bootloader, without providing a way to boot any other installed OS. Linux installers are most times more considerate.

There's no need to reinstall linux. You can boot a linux livecd and reinstall grub or lilo manually. If you are not knowledgeable about these things, there's one special live cd that is oriented to these kind of cases where you need to reinstall or repair your boot loader. Google for "super grub". That assumes that your boot loader is grub though... I know nothing similar for lilo.

Do you know the bootloader that your linux install was using?

Red Hat has been using GRUB - by default - since 7.3 (at least).

Then, booting from the livecd and using "grub-install" should solve the problem.