damaged PST file on CD-ROM

To backup my Outlook file I have copied on a CD-ROM the PST file of a computer that needed to have a complete Windows reinstallation. Unfortunately the file that has been copied on the CD-ROM cannot anymore be opened nor copied from the CDROM to anything else (HD, USB key, etc).
I now cannot get my data back and cannot fix the file on the CD ROM.
Can anyone please give me some advice on how I can get back the data from this pst file?