When a CD is inserted into the CD-ROM drive after Windows has loaded, Windows will not read the CD and My Computer reports the data content of the CD as ‘zero bytes’. The same occurs for discs inserted into the DVD drive. However, if a disc is inserted into the computer before Windows loads, Windows will recognise and read the disc. I can also eject the disc, and insert a disc, and Windows will read the new disc (although the name of the disc remains the same as the disc in the drive prior to Windows starting). The computer is running Windows XP.

Since the problem occurs across the two drives (CD-ROM and DVD drives) it is unlikely the problem is related to the drives themselves. Furthermore, since the computer can read the discs, if inserted before Windows loads, the likely cause of this problem is software rather than hardware. Whenever problems such as this occur with Windows XP, the first procedure I try is to run the System File Checker (SFC) utility. This will search for any missing or corrupt Windows system files and replace the files with good versions.

The SFC utility may need to extract files from the Windows CD during the SFC process. However, we have the problem that Windows will not recognise the Windows XP CD, should it be inserted after Windows has loaded. Therefore, we will need to insert the Windows XP CD in the drive before Windows loads. So, insert the Windows XP CD into the drive and then restart the computer. A message may appear saying ‘Press any key to boot from CD’. As we do not want to boot from the CD, do not press anything and the message will eventually time-out and the computer will boot from the hard drive. Please note: If your computer is a brand-name machine, it may not come with a Windows XP CD (instead, the Windows files have been cached to the local hard drive). In this case, you can ignore the previous procedure as you do not require the Windows XP CD.

Once Windows has loaded, go to the ‘Start’ menu > ‘Run’ and type ’sfc /scannow’ (without the quotes) and click OK. The SFC window will appear and being execution. Once the SFC is finished, it will exit silently with no feedback, so once the SFC window has disappeared you can assume it has finished. Once this has happened, if you inserted the Windows XP CD into the drive, eject the CD and restart the computer (with no disc in the drive) to check if the problem persists.

There is an article on Microsoft Knowledge Base which deals with troubleshooting reading CD and DVD discs: support.microsoft.com/kb/321641. This article may be relevant to your situation and also explains how to change the transfer mode of your drives (from PIO to DMA) which may help resolve the problem. Please let me know if you are able to resolve this problem.