Hi Andri,
Starter for 10, all the options that you removed should be in the config.sup file as they are static, so all the template, format, unit settings, this cannot be over ridden by any other config file
Next I would check that Creo is starting up in a folder that the user has permission to write to, right click on the creo icon and see where it says "Start In" check that this is available and not read only.
If the user is not getting any further than the log in screen it could be Windchill is trying to sync the users workspaces but is not able to write/create the workspace.
The settings in your config, you can bring in one by one and see if there is one in particular that causes the issue or if it is a Windchill connection issue
Hope this helps