Is there a free program out there that I can use to see who is using my internet network that also allows me to kick them off or limit their usage? I know McAfee had something like that, but I don't use that anymore.
Best way to sort this would be to check your routers settings, and check the clients that are connected. Find out your own MAC address and any you know have the right to access the network, and block the rest
Im guessing this is your wifi network, and you have set up a password for it of course....right ?