@Nn49007,

Im not sure what would be causing the other devices on the network to be booted off when connecting, but due to the fact that it is a new computer, I would think that there may be some sort of compatibility issue with your network card and the router. Does this happen when you connect the PC to the network using a wired connection?

I would first make sure that all your drivers for your network card on your PC are up to date. Windows Update will not automatically download updates for your drivers and the setting must be enabled in your settings. Otherwise, this may require visiting the manufacturer's site and downloading the corresponding driver or utility to manage and update your PC. Most issues like this, get fixed with a firmware update for your router or your network card.

After everything has been updated, including the router firmware, try and reconnect the PC to the network's Wi-Fi. If the issue persists, I will need more information regarding your PC such as the model, the network card version, and other information that could be useful to see if there are any known issues. You could also try to disable the 5Ghz band/fast roaming options on the router to see if your PC will connect using the older networks. Lastly, check to make sure that your network is using a common security standard such as WPA2