There are going to be some commands and grub line work involved which you will have to learn. Also do a Google to learn more. Can you boot from the Windows cd and do a fix mbr? This works but you may eventually run into this again. I am no Linux guru unfortunately or I could simply give you the grub fix. Either way, you will have to manually fix the grub with command.
title Red Hat Enterprise Linux AS (2.6.9-34.EL)
kernel /vmlinuz-2.6.9-34.EL ro root=/dev/VolGroup00/LogVol00 rhgb quiet
I was able to boot both linux and xp(which is other) successfully.
Now , by mistake some thing happened like xp partition deletion or something .
I am able to start linux and work but not able to start windows xp.
when I try to start windows xp by selecting that option I get following :
booting other :
Error 22 : NO SUCH PARTITION