DumbMarine I am sorry you have been facing so many difficulties with your After Effects installation. Do you have a case number from your interaction with our support team which I can reference?
To determine why After Effects is failing to install it will be necessary to review the installation logs for After Effects. You can find details on how to locate and interpret the installation log at Troubleshoot with install logs | CS5, CS5.5, CS6 - http://helpx.adobe.com/creative-suite/kb/troubleshoot-install-logs-cs5 -cs5.html.
