not able to connect on browser or ping since installed kali

I have a 32 bit samsung N100 netbook. Earlier it was running Windows 7 but recently I installed kali linux 2020.1b on single boot. Now it is running kali only and hard drive was formatted before I installed kali. I installed kali on it first time. Since I have installed it, I have not been able to use internet on laptop.
The adapter is Broadcom 802.11n
Sometimes I'm able to ping IPs but most often not. Everything is explained below and if something is missing please tell me I will add that in detail.

The problem is I'm not able to connect to internet even though laptop is connected to wifi. (see image)
https://i.ibb.co/7gZJ5zC/firefox1.png

resolv.conf file nameservers are correct (see image)
https://i.ibb.co/M9w4MKR/resolv1.png

When I ping websites, it gives error "Temporary failure in name resolution"
When I ping 8.8.8.8 it gives errors (see image)
https://i.ibb.co/KmmhhNV/ping1.png
Sometimes when I ping it says network is unreachable (happened very rarely)
(see image)
https://i.ibb.co/cY5MvNr/ping2.png

Here is nsswitch.conf file screenshot (see image)
https://i.ibb.co/WkdtsCY/nsswitch1.png

I have two other suspicions: (might be relevant to problem)

First is calendar that is in some weird language. And it shows some date from 2019 whenever I boot. (I know date can be changed and I have tried all above with correct date and time)(see language of calendar)(see image-when it boots up)
https://i.ibb.co/sgyZvX9/Calender-1.jpg


Second concern is when the laptop is booting up it shows errors (see image). I don't know what they mean and if they are related to the problem.

Please help me I'm very new and having problem getting connected to internet is a big problem.