Can't Access Twitter / Facebook Or Youtube?

I've been having this problem for about a month. When I first start my computer, all three sites load fine. After a few hours, the error page comes up stating that Google Chrome (my primary browser) can't load the page. A few weeks ago if I switched over to Internet Explorer, the sites would still be able to load. Now the sites don't load after these few hours in any of my browsers. I've done malware, spyware and antivirus scans and threats did come up, but now there are none and this keeps happening. I also did a DNS flush and it didn't work. This is my log, but my host files are being blocked[CODE]