Galaxy S5 screen stuck on black with a slowly flashing samsung logo. Help?

[Sandy Walker]

My phone was sitting on my desk minding its own business when I noticed that the screen had gone black and the samsung logo was just flashing slowly on it. I can't restart or anything it is completely stuck. The battery area appears slightly warm. Nothing I have tried is working. Anyone know what this is and how to sort this out please?
Thanks Sandy

 

[ironass]

My phone was sitting on my desk minding its own business when I noticed that the screen had gone black and the samsung logo was just flashing slowly on it. I can't restart or anything it is completely stuck. The battery area appears slightly warm. Nothing I have tried is working. Anyone know what this is and how to sort this out please?
Thanks Sandy

Hello and welcome to Android Central Sandy Walker!

The first thing to try is booting into Recovery Mode and wiping your phone's cache partition as per #1.3 of S5 Update Problems - Dummies Guide to see if that solves your issue.