Wifi connecting problems

[prizad]

When i use mobile and wifi has no connected or network slow .My mobile suddenly powered off.  Tell me its solution 

[Saadi121]

Bro your power IC is damaged repair it

[prizad]

Thanks bro

[Saadi121]

No thanks

[Saadi121]

Give me one favour please

[Saadi121]

Click on 3 dots on right and accept it as a solution please

[kkkgham]

I dont know the wifi password because i used the my sister in law's wifi now she changed the password how i know the password?pls tel me