Make your network secure. This is very important for many reasons including preventing people getting your passwards and financial information, projecting your data, preventing misuse of your internet connection, etc. A client had an unknown computer using their internet until their WiFi was secured. Luckily internet provider now usually provide passworded equipment as standard.
Share internet between multiple computers and devices.
Set up your wi-fi or network.
Print, scanner, music access from any PC.
Improve network performance.