This method tested by me if you have Samsung Galaxy A7 SM-A700FD device in that issues of like hang on logo, restarting problem, pattern lock, screen lock then you can use this guide and this without any box you can do just before use remember of must be charged your device battery cause if low device turns off during the process not starting so carefully use.
Before use save your data which is in device cause some impotent like contacts, messages, emails, photos, videos, calendar, notes etc if in SD Card so no need to backup but I suggest first remove SIM Card, or SD Card in device after following this guide or need hardware related that to be working well  which is device volume up, down or power keys for that solve need keys. Must be charged a battery up to 75% now let's go how to solve above issues using this guide ?

Procedure

  • Press and hold Power + Home + Up button until Android System Menu then leave all keys
  • Select "Wipe Data / Factory Reset" from Volume Down button and then Press Power key for confirm
  • Select "Yes — delete all user data" option using Volume Down key and Press Power for confirm
  • You will see Wipe data processing after that done
  • Last select "Reboot System Now" wait for device start normal a few minute
  • Congratulation you are done

Samsung Galaxy A7 SM-A700FD (2016)

  • Press and hold Home + Up + Power button until Samsung A7 Logo and leave Power key only keep pressing continue Home + Up button until Android System menu
  • Select "Wipe Data / Factory Reset" from Volume Down button and then Press Power key for confirm
  • Select "Yes — delete all user data" option using Volume Down key and Press Power for confirm
  • You will see Wipe data processing after that done
  • Last select "Reboot System Now" wait for device start normal a few minute
  • Congratulation you are done
Note : If Hang on logo, Restarting not solve using this guide then follow above relate post