I opened and changed startup programs in Startup Application Preferences. Then after reboot the preferences didn't change, they are the same as it was before. Why I can't change nothing and how to really setup Startup Application Preferences? Thanks.
It sounds like a permission problem, you can try this (from a terminal):
sudo chown [username]:[username] -R ~/.config
If it doesn't help, try to start the "Startup Application Preferences" from a terminal using this command:
You might see relevant error messages there. If the output looks useless to you, you might post it here.