MBP wont display 1080p on monitor any more

I have an early 2011 Macbook pro and a hp 2511x monitor. The setup worked flawlessly before I went off to school. Now that Im back home my macbook wont display 1080p on the monitor, only 720p. While attempting to display 1080p the monitor screen is blank but I am able to move my mouse over to the external dispaly just fine, just no picture. My mac will display 1080p on other external monitors & the monitor will work fine with other computers or xbox on 1080p.

Just upgraded from 10.7 to 10.9 and still not working properly.

Connecting from mini display to hdmi

Thanks!