Laptop can get inteet from other wifi, but not our home

So my sister got a new laptop, and it has been having trouble getting onto the inteet. So, it is getting an IP via the router's DHCP, and says it has inteet connection.

But, when i try and ping the router, it is getting timeouts, and then every maybe 12 or so pings, it will get a reply, but in 500-2000 ms.

I have uninstalled and reinstalled the wifi drivers, reset winsock reset, flushdns, iprelease/renew, deleted he arp cache etc. Uninstalled AVG, and I just can't figure it out for the life of me. It can connect to her hotspot, and her schools wifi, and everything else in our network works, except her laptop.

I have also reset and reinstalled windows, and still nothing. I have no idea, so any help would be great

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