Hl2.exe error when I get to the portal opening when i start new game

[rowan789]

I just downloaded portal for free from steam any idea why it isn't working and how to fix it?
Once the countdown finishes the game freezes and then comes up with hl2.exe error

 

[Dekstar]

Try verifying your game cache. From Steam's Library tab, right click Portal and click 'Properties', then click 'Local Files', then 'Verify Integrity of Game cache'. If you've got files missing, they should be redownloaded automatically.

Then just try restarting the game and see if that fixes it.