Unfortunately, a crash is one of those things that can have multiple reasons and sometimes - the solution is simple, but more often than not - the root of the problem isn't very easy to find.
I'm just going to list the normally recommended procedures that you should carry out if you really want to fix your crashing problem:
* Uninstall everything, HL/CS and ESF.
* Reinstall HL and update it to 1.1.1.0 or reinstall CS and update it to 1.5
* Install the full version of ESF Beta 1.1
* Make sure your graphic card's drivers are updated. If you aren't sure about dealing with drivers - it's better you skip this step as you might end up making things worse.
* Make sure you have the updated DirectX installed after you installed the updated graphic card's drivers.
* Make sure you're running ESF on OpenGL and on a STABLE resolution.
* Try decreasing gfx and beam quality settings from MULTIPLAYER > CUSTOMIZE > ADVANCED.
If you do all of these things, you should decrease the chances of a crash by a great extent. But I still cannot guarantee that this will work 100%. I hope you are able to fix the problem, feel free to post here if not.
Good luck. :yes: