I installed the grub, still it is not working. But i found out in the system that the win xp has changed all the drive name the one bfore installation was c, e, f,g, and after installation was c,d,e,f.
I changed the drive names using the computer management of win2k but still the rh does not boot from the hard disk. But the same does it from the floppy. I even tried the bootsect.lnx but it is not working.

Is there any way, re install the boot alone to the partition were rh is there. Because, i feel when xp change e drive of the old one to d drive, it must have disturbed the setting of the linux partition.

Boot Red-Hat off the Boot Disk you made at startup (you did make one i hope)... then do a "grub-install /dev/hda" from the shell.

yes i did it and it is working only one precautionis rearrange your hard disk name c: d; e: as it was before installation of the xp