Mmm that's weird.
Okay you can try this.
Close Origin.
Open your "Origin Games" folder (ex: C:\Program Files (x86)\Origin Games\Plants vs Zombies Garden Warfare)
Copy the entire folder, put it somewhere else.
Open Origin.
Uninstall PvZ.
Close Origin.
Copy the Plants vs Zombies folder back to "Origin Games"
Open Origin
Click "Download/Install", it will skip downloading since the files are already there and jump to installing.
If you have quick internet you can just uninstall and then redownload the entire thing again.
That should certainly put things back to default / autodetect I would think.
*edit
Or you could try turning Windowed mode on from that setting file from above. Then if it opens the game you can modify the settings from in-game options back to fullscreen & proper resolution.
