It could just be the sharpness. Check the TV menu for "picture" and set the sharpness back up. Your TV might keep getting reset. Keep changing back the sharpness.
If you use your remote and select menu you can play around with the settings until you can adjust your focus, once you are happy just press menu to exit.
most newer model t.v had a "reset" button to put everything back to manufacture settings. look in your menu on your t.v and find this option. you may also refure to your owners manuel.
