Samsung S6 Help

Jun 5, 2018
When I turn on my Samsung S6 I get a blue light and a dead screen, I also get the startup sound. Half way through the sound it stops and plays again. I read articles that said hold the power and volume down button until the light goes off. The light does go off but after 5-10 seconds it comes on and the dead screen and recurring sound is back too. I don't know if my warranty is still active. I got this phone as a gift and I really need it.