You have bought an upgrade package from Website X5 by Incomedia. You have tried many times to try to load version nine, including from a disk they sent you. You keep getting an error message, "Unhandled exception has occurred in application could not load file or assembly System Core, Version=220.127.116.11 Culture=neutral, Public key token=b77a5c561934e089 or one of its dependancies The system can not fine the file specified."
You have tried re loading service pack three onto your Windows XP system. You do have version eight of Website five running, and are reluctant to remove it in case you can't get it back up again. Make sure you have Microsoft .NET Framework 3.5 installed.
Also, I know you installed XP service pack 3. You can double check to make sure you have all Windows updates installed. If you install .NET framework 3.5 then try using Website X5.
If you don't have Windows updates set to automatically download and install, then please visit previous windows updates web site. Missing updates for any windows components that Website X5 uses, might be causing your problem.