HELP!!! hda error!!!

[Giovanni Alzetta]

Well, one my friend have 2 hard disk. So I installed fedora linux on the 
second. Now when I start fedora I see a hda system control than an error and 
something like this:
"enter root password"
"or type ctrl+d"
if I press ctrl+d I reboot the computer. If I enter the root password I'm in a 
"read only" file system, so I can't do anything.
I do that: install fedora, at the start I saw a hda control, but nothing of 
strange, than copy some files from windows to fedora and erase those files in 
windows. Than I reboot the computer and BOOM!!! The error come.
So I tried with knoppix to copy files from fedora to windows, but I can't go 
in the home, I just can't read files from that home.
So there are two solutions:
-how to read files with knoppix?
- how to erase the error with fedora
Thanks for help!!!!!! (please answer!)
bye bye
P.S. I think that the hard disk of the my friend don't work very well, because 
windows become crazy every 2-3 months. (and sorry for my bad English)