First to clarify a few things. It sounds like you have the computer up and running with a new drive and have moved the bad drive to the secondary IDE channel and can see it but can't access or see any of the files on it.
It might be beyond a simple repair or close to it. First find out from your friend what is the most important thing that they need recovered.
Next what I would probably
do (it's so much different to see these in person than through a forum
) is plug in an external drive at least as large as the bad drive. Then I would boot the computer using a Puppy Linux LiveDVDhttp://puppylinux.org/wikka/livedvd
Then I would see if I can mount and see the files on the bad drive. If so, I would immediately copy the specific files that are 'most wanted'. Then I would get files of secondary importance.
If I can't read the bad drive, I would try Pudd to copy it to the empty external drive. MENU>UTILITIES>PUDD
Then try to see if the files are readable on the external drive. If not, then I would get a copy of Testdisk for Puppy and try it (or Photorec which comes with it) on the external drive and place the bad drive on a shelf in case you need to try recovering it again later.
The main thing to remember is that if you are fortunate enough to access and copy files on the drive, you should get everything that is important as quickly as possible because it may be your last chance.
If you try this and have any problems or questions, let us know.