If you have two or more computers then you may want to network them. This would enable you to share files, share a printer and share your internet connection. This can be done in two ways – the computers could be hard wired by cable, or connected by a wireless system. With a wireless system you could say, use a laptop anywhere in the house or garden and connect to your main computer situated anywhere in the house.
A wireless network offers advantages and disadvantages compared to a wired network. Advantages of wireless network include mobility and elimination of unsightly cables. Disadvantages of wireless include the potential for radio interference due to weather, other wireless devices, or obstructions like walls, unless secured properly they are more susceptible to other nearby wireless users using your system to browse the web or hack your system.
I can install either system, and if using wireless, ensure it is properly configured to prevent unauthorized use by others nearby.