Final answer:
Internet Connection Sharing (ICS) is a Windows service that enables a computer to share an internet connection with other devices, acting like a router. It's useful in a small network environment where no dedicated router exists.
Step-by-step explanation:
The Windows service that can convert a computer into a router and share an internet connection with other computers on a network is called Internet Connection Sharing (ICS). ICS is a feature in Windows that allows multiple computers to connect to the internet using a single connection through one computer network. This is a form of network address translation (NAT) that enables internet access for devices by assigning them unique IP addresses while they share a single public IP address.
When you enable ICS, the host computer becomes a quasi-router, allowing other devices to connect through it. This could be especially useful in a small office or home network where there isn't a dedicated hardware router available.