Any device that connects to the computer, such as a printer, scanner, monitor, keyboard or mouse.
Since the USB port on Elias's computer works for other devices, and the Belkin NIC (Network Interface Controller) card works on other computers, Leo thinks his problem is with drivers. When installing devices via USB, it's important to not plug the device in until the drivers have been installed. Elias did this correctly, though. Belkin support suggested that it could be a firewall preventing the card from accessing the internet, but Leo doesn't think this is likely. Elias should make sure he has all of the latest drivers for the correct model.
No, the USB is not for connecting to the TV. That's for viewing photos from a USB thumb drive. She'll need an HDMI connection, but her Dell Latitude doesn't have an HDMI out. Many laptops will have VGA out, and it's possible that her TV has a VGA input. This would work, but it isn't the best way to connect it because it's analog, not digital. Her laptop does have DisplayPort for video, though.