There are many ways to share content from a Windows computer to a TV screen/projector.
Using a LiteShow 4 that would wirelessly connect a computer to the LiteShow network. Windows 7 has the ability to both connect to a wired and wireless network. I had a friend who has this and it works perfectly with his desktop configured with a usb wifi adapter. You have to install the supplied software for this to work and then put in the code.
Connecting through the video out to TV screen with a VGA or other adapter cable.
Using an Apple TV to connect through the network. This works very well and doesn’t require any additional hardware or software. This works only for Macintosh devices. Windows devices wouldn’t see an Apple TV by design. You might be able to use third-party software like AirParrot to make this work. It supports streaming to a PC.