I agree with Greg - it sounds like you may have used a "Third Party" (Not Windows XP Default) Copy Application, and it archived data on the CD according to it's own Utility.
Ultimately, you would need to use that Archiving Application's Utility to view the Data on the CD.
If you used the CD Utility which is Windows XP's Packaged (comes with Windows XP), maybe there were issues with the Disks, and / or Data, at time of Copy (Write to CD) - but Windows did not display any error dialog boxes.???
If CD-RW, there may be issues with the Data strings (especially if Data was written in several different sessions), which is confusing Windows as the OS views the FAT.
Also, if compiling Data to CD-RW with a Third Party Application, Windows will stare blankly at the Disk - even though there is proper Data on it (just needs to be run through the same Utility).
Most of the better Archiving Applications will set a "Self-Installing" Data Reading Utility on the Disk, which will prompt for user input to install the utility, once the Disk is accessed.
If you do use an Archiving Application (as opposed to the Windows XP Standard App.), be sure to select "Read On All PCs" option.
Questions / Comments:
1: Do you Archive (Copy Data to CD) by first selecting the data, then performing a "Send To" action (Send To CD-R)?
or via Copy / Paste action?
2: Is the Disk Media CD-R, CD-RW or DVD-R?
3: Make sure not to use Audio type CD Media for Data file Archiving.
4: Have you been successful with other CD Archives?
5: Did you try reading the Data after the Copy was complete?
6: Do you reboot your machine prior to Archiving?
7: Have you tried to read the CDs after a recent Reboot?
8: Can you try to read the CD Data on another PC?
Scott35