I had this problem long time ago with Battlefield 2: I logged in to my account, chose a server to play on, maybe even played 10 minutes and then the game crashed instantly without any error. This problem only occours to those of you that have dual core procesors (quad core..etc).

Here is what you have to do:

Enter the game, login then pres CTRL+ALT+DEL. From your task manager, swich to the PROCESSES tab and search for BF2.exe . Once you found it, right click on it and select SET AFFINITY.Leave only ONE processor selected for BF2.exe. Get back to the game.
Remember to always do this before playing Battlefield 2. Have fun!