Why am I unable to connect to a WiFi signal?

I got this Chromebook around 7 years ago, going off of reviews online. But I soon discovered that at times I would be unable to connect to the WiFi - or see any networks at all. Everytime I'd try to reboot, one of a few things could happen - 1) It would be okay for 30 minutes or so, then start having WiFi issues, 2) The Wireless icon would grey out, and I'd try to toggle it back on, only to have the toggle automatically toggle back off, or 3) I would be unable to see any wireless networks, even when my phone was able to see them. It got so bad to the point where I stopped using it and bought a new Chromebook entirely, but even now when I try to boot up this one and set it up, it has issues with connecting to the WiFi.