Fix the “HL2.exe has stopped working” error
Is it the case that whenever you try and run any source game it says “hl2.exe has stopped working“? It is highly likely that you are using Vista. But this doesn’t mean that this is yet another bug in Vista! Also you would have tried reinstalling the games, uninstalling Steam, Disabling Anti-Virus, verifying the GameCache and so on but nothing may have worked. Below is a simple and guaranteed fix to your problem.
Go to C:\Program Files\Steam\steamapps\username and move any game that runs off of hl2.exe to C:\Program Files\Steam\steamapps\common. After this, try to run the game. Don’t be scared to see a black screen, initally. Just wait it out and the game will end up loading and from there on your game will work perfect and you will never encounter the message “HL2.exe has stopped working”.