My 320 GB My Passport Essential isn't opening

My external 320 GB My Passport hard disk was working totally fine but 3 days back when I connected it Its volume label changed from My Passport to Local Disk and I am not able to open it.

I am using Windows XP SP 2 so I checked it in Disk Management where it was showing it as a Healthy 300GB partition without telling anything about File System. I also tried  chkdsk F: /F  which was able to detect the volume name and  NTFS file system but ended with an unspecified error without fixing it. I tried chkdsk again but now it is showing more unreadable file segments.

I am having a lot of family pics and some very important documents on it  which I don;t want to loose. I don’t know what to do now. Please help me.

I forgot to tell that I bought  this HD 2 years back and  it is still in warrenty period (i.e.) but I have lost its recipt so may be I will not be able to use warrenty cover for this. Please help !!