i installed fedora core 4 on my system.
After the successful completion when i rebooted my system,then there simply comes a screen(terminal like) with prompt as
GRUB>

what to do ??

Sounds like you selected to install GRUB to the first sector of your Linux partition instead of MBR. Did you want to dual-boot with XP while retaining the XP boot loader?

If not, boot from the Fedora CD/DVD (which is ancient by the way, the latest version is 7), select rescue mode, then install GRUB to the boot drive's MBR with grub-install devicename (usually /dev/hda, sda or something like that).

i didn't get ..."dual -boot with xp while retaining the XP boot loader"...
and also what is "MBR"??

I had the exact same problem, but I just got Fedora 7 to work.

Download a LiveCD first, and then install Fedora from that. thats what I did :3

Hope that helps!

Do you have XP also installed, and want to decide which OS to boot using XP's boot menu?
Master Boot Record, the first sector of the whole hard disk drive.

how to go in rescue mode..??

Ok, first of all You'll need somewhere to put the Linux OS. I partitioned my HDD in Vista on my laptop, so you'll either have to do something like that; getting another HDD for your desktop computer works as well.

Once you have space set up, download a live CD of the linux distribution you want to download (theyre normally around 600 to 700 MB so they can fit on one CD). Once you've downloaded the live CD, go ahead and burn it using a CD burner. Shut down the computer and restart it booting from the CD. You should see a new desktop and layout of the version of Linux you want.

The CD SHOULD appear on the desktop (at least it did with mine, i used Fedora core 7) along with an option to save files to disk (or something like that). Double click this icon to activate it, the follow the onscreen instructions. Make sure that you save the OS on the designated space (HDD partition or otherwise).

Finally all you need is an internet connection to look for any updates and drivers etc. Thats all that I can recommend for you :3

Oh, and if you're trying to install Linux on a Dell computer, don't bother. I've been trying for three months straight with no avail. I heard dell is supposed to have a file to prevent you from installing other OS's on it. if you somehow DO manage to get Linux on a Dell, please let me know (my dell doesn't allow me).

So yea, good luck and happy learning