A user is unable to get a laptop screen to display on the conference room...

When a laptop screen is not displaying on a conference room TV despite being connected to a wireless HDMI dongle, the issue is often related to the TV being set to the wrong input source. Since the in-room computer's desktop is displayed, it suggests the TV is currently set to the input source used by the in-room computer. Changing the TV's input source to the one associated with the wireless HDMI dongle connected to the user's laptop is the simplest and most direct approach to resolve the issue. This does not involve adjusting network settings or hardware configurations but rather selecting the correct input source through the TV's input selection menu.