Hi -
>
> I am asked for ^D (Control D)
>
> Then I am asked for root password.
>
> Then it opens on text mode.
>
> Now what I have to do? I am in trouble – all my files would be lost.

Boot using LiveCD and post the output of command "fdisk -l"  here.

And also attach external harddrive/pendrive - try and mount your original partition and copy important files to external drive ,if any.

Since you have said something about gnome - I would suggest you to edit /etc/inittab file & change it to text mode.

from something like
id:5:initdefault:
to
id:3:initdefault:

Now try and reboot again and see whether that works.

If it still stops in the middle and asks for passwd & displaying message like "you need to run fsck" ?.
Do run fsck command on the partition.

> I was trying to upgrade from fedora-14 to fedora-15

Why did you upgrade from fedora14 to 15 ? Any specific reason?

>  – all my files would be lost.

It should be possible to get them back without using recover tools. (90% chance unless you have re-formatted partition during upgrade).

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Cheers,
Lakshmipathi.G
FOSS Programmer.
www.giis.co.in