Proxy not working

I have been trying for weeks to fix my proxy internet stuff but nothing works! I've tried evrything but half of it is all blocked by proxy. I've gone to settings but above that and above the automatic proxy setup it say "some settings are manages by your organization." And trust me I've tried to find fixes for that as well but nothing. Some of my computer apps don't work saying the internet isn't connected about half the websites work but nothing else. I've tried to run scans but even they don't work because of the internet! I really hope you can help I'm desperate!