The EA app overlay is known to cause conflicts with the game, preventing it from launching or causing it to crash at startup. Disabling this overlay is how I managed to finally fix the issue.

1. Open the EA app.
   
2. In the top-left corner of the window, click on the burger icon and select Settings.
   
3. Under the Aoolication tab, look for the "Enable in-game overlay" option and uncheck it.
   
4. Close the EA app window.

Once disabled, try launching Dragon Age 2 again from Steam. Hopefully this is the only fix you need.

Sometimes, issues with the EA app itself can prevent Dragon Age 2 from launching properly. A fresh installation of the EA app may fix corrupted files or settings that are causing conflicts. This fix seems to have worked for some people in other discussion threads

1. Open Control Panel and go to Programs > Programs and Features.
   
2. Find EA App and click Uninstall. After uninstalling, restart your computer.
   
3. Try launching Dragon Age 2 again from Steam, which will reinstall the EA app and hopefully fix the issue.

Some players have also reported that changing the renderer from DirectX 11 to DirectX 9 solved their issue. While this did nothing for me, it could be the fix for you.

1. Open Steam on the Library tab and locate the game.
   
2. Right-click on it, select Manage and then Browse local files.
   
3. Open the folder bin_ship and launch DragonAge2Config.exe
   
4. Once it opens, click on the Video tab and change the renderer to DirectX 9.
   
5. On the top of the window click on the Dragon Age II and on Save Dragon Age II Settings.
   
6. Try to launch the game.

This game is ancient and EA couldn't care less about supporting their legacy titles...

The most effective fix I believe is to disable both the EA Overlay, as this seems to be the most common culprit. If that doesn't work, you can try the other troubleshooting methods.

Still having no luck? Well, you could always reach out to EA or Steam support, but don’t be surprised if they just tell you to reinstall the game.

OR just play it on Linux which surprisingly runs like a charm without any headaches.