macbook air crash immediately after start

My son's Macbook Air crashes in 5 seconds after push the power button for starting the Mac. Gray apple pops-up in 2 seconds and then MacBook gets dark screen, after few seconds, Macbook tries restart and same effect up-down-up-down... happends continuously.

Problem started today. Is it possibly power or battery problem, mother board, flash disk or...? How to identify problem area. Mac is about 1,5 year old only.

Safe mode boot does not work either.

br Kari