This method tested by me if you have Micromax Q372 Unite 3 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

  1. Press and hold Power 3 seconds only then Immediately Press Volume Up until Micromax Logo leave all keys after you can see Android System Logo
  2. Press Home key for Android System Menu
  3. Select "Wipe Data / Factory Reset" from Volume Down button and then Press Option button (near Home key) to confirm 
  4. Select "Yes — delete all user data" using Volume Down key and Press Option button (near Home key)
  5. You will see Wipe data processing like below
    • -- Wiping data...
    • Formatting /data...
    • Formatting /cache...
    • Data wipe complete.
  6. Select "Reboot System Now" from Volume Down and for confirm Option button (near Home key) wait until Star in Normal Mode
Note : If  Hang on logo, Restarting not solve using this guide then follow above relate post