Screen Constantly flashing

A

AC Question

I have a rooted (not by me) Samsung Galaxy tab SM - T800. I gave it to my daughter who wanted to remove my stuff from it so I clicked on Factory reset. Now all that happens is that the screen constantly flashes with what appears to be the words TEAMWIN.
I have tried to switch it off; have pressed the up vol/home buttons simultaneously; I'vwe connected it to my laptop which won't recognise it.

I don't know what i can do.

Please help.