Mac won't connect to WiFi, what should I do?

Question

macOS

Guys, five days ago I bought a macbook, updated to 10.13.5. I put a utility for writing to an external ntfs hard, asked for access to the kernel extension. After I gave access, the Wi-Fi fell off. I rolled back to 10.13.3, which was even before the installation of all this gimmick. There is still no wifi. Installing a new version via command p fails, there is no Internet. What to do? And how does such a rollback happen that problems remain?
P.s. Yes, I returned to the system settings.
If you help, I won’t remain in debt, I’ll throw 500 rubles for kiwi.

Answer 1

They gave little initial information. If the problem is that it sees networks, but cannot connect, then check with another router, connect to a smartphone, and so on. If the problem is only with your router, then try reconfiguring it, resetting it, etc. If the problem is with all routers, make resets, rearrange the system from 0, format the disk. You will need to make a bootable USB flash drive, search the internet for instructions, the easiest way to do it is on a poppy. If the problem remains, then it is hardware, then carry the poppy under warranty if you bought a new one with a warranty.