"hl2.exe has stopped working" when I start a LAN-game.

So whenever I start a LAN-game to play with my friends my game crashes randomly. It could take 5 minutes, it could take 5 hours, but in the end, it will crash. It never crashes like this if I play on another server or singleplayer.

Any known fix to these problems?

Intel Core2 Duo CPU T8300
2.40 GHz
3GB RAM
Windows Vista 32-bit

There are some suggestions here: https://support.steampowered.com/kb_article.php?ref=9402-MKEN-1517