Technical Support laptop keyboard wasn't working

[user50857]

i have this dell inspiron i5 7th generation.
motherboard: BAL21 LA-D802P REV:1.0(A00)
the keyboard wasn't working.
i removed the battery connector and then removed keyboard connector.
i connected the keyboard coonector again but now Fan works hard and after some seconds it restarts.
i remored ever connector from the motherboard including ram and bios battery, but it still does the same thing.
i dont understand tf is going on

 

[user50857]

ITS OK I FIXED IT

 

[Hosein Asadolahi]

What was the problem?

 

[user50857]

Bios battery was 0V. Actually i dont understand why some dell laptops act strangely because of bios battery. It is supposed that it will turn on at least. I attached the new bios battery and it was doing the same thing again. But i waited some minutes until it turned the screen on after some restarts.