The screen goes and come frequently

[ehsanehsan]

Dear all,

I could not turn on my device. As I reset the device, holding all [right], [left], [2nd] and [on], it turned on suddenly.

But now, the screen goes and come frequently. Sometimes it goes and does not appear, so I reset it again. This is my new problem. The screen turns off gradually in about 3 seconds.

Please help me if you know about the problem.

Best wishes