Originally posted by DR.V
What I did was , I installed Fedora Core 4 from Windows XP.
What exactly do you mean by "from"?
Also, when you installed Fedora, did you not install a bootloader (GRUB or LILO, I'm not sure what the default for Fedora is)?
If you want to reinstall NTLDR:
Boot from your XP CD
Go to the recovery console (you'll see a message like, "press R to repair an installation")
Log in with your administrator password
At the DOS prompt, type "fixmbr" without the quotes.
You won't be able to boot FC though (unless you set up NTLDR to boot it, search Google if that's what you want to do). Other than that, I'm not sure how you can reinstall GRUB/LILO. Fedora's CDs may have a repair feature, but I don't know.
Edit: too slow!