Exclamation Screen Off Centering and battery draining.

Hello i am new here,i purchased a new nexus 7 2012 3 months back,and have used a few other devices in the past.my problem is that the screen looks off centred after i did a system reset i noticed it .i could not find any other forums,posts except for a few.


But No answers anybody please help me.

and also the battery seems to go fast like only 50%charged..discharged and the battery level indicator shows full.

please help me.tab is rooted supersu.,custom recovery,android 4.4 please HELP