Game Error: HL2.EXE has stopped working
Game crashes can have many different causes depending on your system. The best way to determine what the issue is being caused by is to follow this guide first:
There are several Hotfixes available for Vista users and Vista users with Nvidia cards. We recommend following the Windows Vista Guide in its entirety.
Certain anti-virus and anti-spyware software such as Norton/Symantec, AVG 7.5, Avast, Spyware Doctor and Nod32 have been confirmed to cause game crashes with Source engine games. If disabling your anti-virus and/or security software does not help, you may want to consider completely uninstalling these applications until an update is released by the anti-virus software developers that resolves these compatibility issues. More information can be found in the Troubleshooting Game Crashes FAQ topic that is linked above.
Graphically intense games such as Half-Life 2: Episode Two and Team Fortress 2 require a large amount of your system's resources to run. Having background applications running while you play can often result in the game engine competing for system resources with other applications. Often times this can result in the game crashing because there is not enough system resources free for the game to utilize. Please follow the guide below for more information:
It is also important to make sure that your system has enough paged pool memory available. Please follow this guide for more information.