we really require more info on the computer,model, operating system, any DVD/CD mediaplayer/ recording/ playback software installed etc
you could try this software patch from here can solve the problem sometimes, it was aimed at windows XP, but the problem is still there in Vista unfortunately
go to this web page
and Download XP_CD-DVD-Fix.zip
and save this file to your hard drive. Navigate to where you saved it and double click the file to extract the contents. Locate the EXE file you extracted and double click it. A confirmation dialog will appear when the script is done. You may need to reboot for the change to take effect.
This utility is only intended for Windows XP. You may need Administrator level access to use this utility. If you do not have Administrator level access, the program will say it is finished, but will not have made any changes.