You will need Daemon Tools ( this that acts as a fake cd rom )

google daemon tools its free.
This will try to install a search bar, click no unless you want it...
After your computer has rebooted you will now see a blue lightning bolt
next to your pc clock on the right. The program has been successfully installed... next....
You will need to download the actual 'fake' battlefield 2 cd to use with this program.
*note you will need winrar to extract these files.

(once winrar is installed right click the downloaded BF2 cd key and select extract here )
You can get the battlefield 2 fake cd at gamecopyworld dot com click game index and search for battlefield 2 mini image.
You can do the same with special forces

Now that you have installed daemon tools and have downloaded and extracted the battlefield 2 mini image ( or the SF image )

right click on the lightning bolt icon next to the clock and click mount image. select the battlefield 2 mini cd ( from where ever you extract it )You can now play battlefield 2. & yes this works online.  remember to patch your game.