It would help if you told us what version of windows was involved, what software was used to write the disk, what CD/DVD burning software is on the machine, and whether the machine has packet writing / reading software (CDRW) software installed
I'd guess that the disk has been written with packet writing software and your PC can't read it as it does not have packet software installed
Alternatively see if this program will crack open the disk
Its a trial - you may have to buy the entire program to extract the data, but the trial will tell you if anything is recoverable
Data recovery software for CD / DVD / BD / HD / Flash / USB drive / MMC, SD, Compact