Would using a wifi dongle to connect my computer to a wifi enabled router make my computer more vulnerable to someone who wanted to gain unauthorized access to it, than connecting to the wifi router with a cable?
The answer of this question depends on your usage of the router.
First I want to mention that it depends how you implemented your wifi connection. If you are using WEP it's like you are using no encryption. Sadly there are so many problems with this standard that you should not use it at all. If you switch to WPA2-AES with a PSK you got better security at all but that's also not unhackable. If you want to increase your routers security I would recommend to disable the WPS function. In many hacks this was the entry point of some hackers but in newer versions security got better at this point. Anyway I would still recommend to deactivate it.
If you are connecting your PC with a cable with the router and disable the WIFI I would really say this is the best solution for your LAN. So you closed one entry point. It's like closing one door.
If you want to leave your WIFI enabled I would say Yes it makes a difference but just if someone got your WPA Key, so he will be possible to decrypt your packets. But if that happens, your PC will not be safe at all. No matter if u are using a cable or a wifi connection.
- Try using a long PSK (WPA Key) for your Router
- Disable WPS. It's anyway just for comfort
- Alter your PSK every year or if you think you are compromised
- Don't save your Key in any Keyservers
- Alter your standard admin user and password at the router
- Disable UPNP services
- Disable web access throught WAN
- Update your router!
- Disable SSID broadcasting
- Use MAC filtering
- Disable TKIP
Hopefully this information helps you. If you got more questions or want to get more details about it feel free to ask!