To disable Autoplay CD in Windows XP follow these steps:
Click Start and enter REGEDIT
Then go to:
HKEY_CURRENT_USER\SOFTWARE\MicrosoftWindows
\CurrentVersion\Policies\Explorer
Create a new value called: NoDriveTypeAutoRun
Type is: DWORD
Value is: oxooooob1 (177)
You have to need reboot the system to make the changes to take effect. You have to do these steps with Administrative privileges.