Latitude 3379 win 10 ; boot loop ; fail to boot

HELP!

I have a Dell latitude 3379 on win 10 that goes into a boot loop.

When I turned on the laptop by the power button, on/off button on the side,

1.  white led lit up, keyboard lit

2. it goes to the Dell logo,

3.Dell logo went out,

4. black screen,

5. fan going on high speed, 

6. White led went off, keyboard off

7. White led blin 4 times, change to amber.

8. Pseudo power off

9. White led lit/keyboard lit again

10. Repeat to step #4

This happened with power adapter plugged in and out.

Long Pressing the power button sometimes work, mostly no effect.

If I'm able to totally shut it down, when I turned it on again an pressing F2 on Dell logo, the bios bios displayed "Time-of-day not set" is it CMOS batt problem?? 

But if I fix the date, and restarted it, it goes into the boot loop again..

This accident already cost me an important job interview, where the interview require me to do an analysis puzzle in one hour. I have to use my son laptop, which is an older Dell 5447 to redo the analysis. Finally I manage to finish the analysis in 1:52 , hope the recruiter understand my problem, even though I doubt they will.

PLEASE HELP! I'm one of your loyal Dell laptop customer, this is my 3rd laptop.