process sysem not responding, activity media storage not working.... samsung s3 problems

[AC Question]

Please can you help my samsung s3 keeps turning itself off then the above messages keep appearing. I hasve tried leaving the battery and sim card out of the phone, Have now cleared my phone of all data etc and reset to factory settings but still happening.thanks Hayley Owen

 

[B. Diddy]

Welcome to Android Central! Maybe there's a corrupted file on the external microSD card (if you have one inserted). Unmount it in Settings>Storage​, then remove it, and reboot.