We have a large TV at work - I connect my laptop to it to share my screen during meetings. Until today, my laptop display has been duplicating to the TV automatically when I connect the TV cable to the laptop. The display resolution would decrease automatically to be compatible with the TV.
Today, however, it's stopped working. When I connect the cable to the TV, the display extends rather than duplicating. Using the Win+P key combination (or Fn+F7 on my Lenovo laptop), I can choose to duplicate the display - but when I do this, it ends up only displaying on the laptop. I can get it to display on the TV by hitting Win+P and choosing "projector only", but then I can't see what I'm doing on the laptop screen.
I have a Lenovo W520 laptop running Windows 7, connected to the TV using a DisplayPort-to-HDMI converter cable. The TV's native resolution is 1280x720; the laptop's native resolution is 1600x900.
I've tried booting with the TV cable already connected; I've tried manually lowering the display resolution on the laptop to 1280x720 before duplicating the display. Neither works.
Does anyone have any other suggestions?