by, "CD initialises installation", do you mean you see an adobe message?
No. The "Initialising Installer" box simply disappears when the green progress bar gets to the end, and nothing comes up to take its place.
Thanks for replying anyway.
Graham if you are not able to get beyond the Initializing Installer message then you will want to review your PDApp.log. You can find details on how to locate and interpret your log files at Troubleshoot with install logs | CS5, CS5.5, CS6 - http://helpx.adobe.com/creative-suite/kb/troubleshoot-install-logs-cs5-cs5.html.
If you have any specific error messages you would like assistance with then please feel free to post those errors to this discussion.