Hey, there ...
My cousin laptop failed - can not boot into the windows and freezes on loading files / windows. So, from LiveCD I was able to see the partitions,and thought it's a windows problem. BUT! - I managed to boot from a windows installable CD, chose "Fix startup errors" - it gave me an error. (Input/Output error.) ... and from then on - I can't see the previous partitions on the HDD. Tried different live CD distros - no result.
So, I'll install something - most probably some linux - but is there a way to save the files? ... at least the pictures, cause all the other data is trivial - music and movies. But the images are unique, so if there is any way to save them - it would be great.
Thanks in advance ...

Try Testdisk, link below to a tutorial which has a download link on the left:

http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step

With installing (or trying to install) things to the harddisk you will lower the chance of successful recovery of the images. As mentioned above, try if you can see the files with Testdisk, if that doesn't woork you might be able to recover the files with Photorec.
While Photorec scans the disk you might want to use the time to think about proper backup strategies for your friends important data.

Definitely do NOT install anything on the harddisk. Use LiveCD's only, or install the problem disk on a different computer (NOT as the boot device though).

Is the disk not being seen, or just the partitions on the disk that are not being seen?

If the disk itself is a problem you could try spinrite from grc.com. This program will try everything possible to correct errors on the harddisk. And I understand they have a money back garantee if it doesn't give the desired result.

Connect it as a second HDD to another computer (preferably running a linux OS as there are no virus problems). If you don't have another computer try a friend - it's very simple and safe. Boot up the other computer and you will see your HDD and have access to all the image files which you can copy to whatever you want.

Recently, I had a similar problem with a friend using Windows Vista. There was no way to boot up from any kind of boot up. His Vista was rotten and I have no clue why it happened...
I took the disk out, put it in a USB external box, and tried to read it from my laptop (which has both Windows 7 and linux Ubuntu installed).
I could not access (not even see it) the partition from Winwdows.
But I could fortunately read it without problem from linux (Ubuntu), then save all the data to another disk.

Then I tried to install linux on my friend's computer (as double boot, like mine, hoping to keep Windows if possible). But I could not, because the installer could not modify the Windows partition (signalling an error on it).
Finally, I forgot about keeping Windows, so I installed a linux Ubuntu system by reformatting the disk, I copied the data from the backup, and everyhting worked perfectly.
My friend has very little knoledge and practive on computers and adapted very easily to linux... and all his data is there (including Windows Mail address book that his Windows was no longer able to handle, but that Thunderbird has no problem with).

THE MAIN POINT
As already mentioned, if a system has such problems that one cannot boot, the FIRST THING TO DO is to take the disk out of the computer, read it from an external box (or putting it as a second disk in a desktop computer) and save all the precious data, before trying to install anything else on the disk.

1. Well, I never tried to install anything ... only checks from the live CDs and fix errors from the Windows 7 Install DVD.
2. I see the disk, but no partitions on it. (I think the whole one was unallocated space ... but not sure now.)

Anyway, I tried with TestDisk - and for that second partition -> D:\ -> which appeared to be logical - TestDisk showed me "Can't open filesystem. Filesystem seems damaged.". Started DeepScan - but it would continue for several days ... so I canceled it.
Then - I tried with PhotoRec - and voila! ... I was able to save all the files - or at least most of them ... of course, the names were changed, but that's not a problem ...

Thanks anyone ... aaaand ... you can mark this thread as "solved" ...