I guess it would be easier to stop the thing from starting up altogether than it would be to hunt down all those additional processes it launches and fails to stop when you close it. So what I suggest is, go to the start menu, pick Run, enter msconfig, switch to the Startup tab, and uncheck those items that seem to have something to do with Orange synchronisation (or rather, to be on the safe side, uncheck everything that has to do with Orange in general: those are not system-critical processes, and you'll be able to re-enable them afterwards).
After you've done it, restart your system and proceed to Control Panel -> Add/Remove Programs straight away. You should be able to make Orange Synchronisation go without any problems.
Then restart your system, run msconfig, and re-enable those Orange-related items that have survived the process.
In case the program should be acting up for you and refuse to uninstall even after you remove it from startup, run services.msc the same way you ran msconfig and stop all Orange Synchro-related services.