Many people report problems with getting alt tab to work. There are two solutions. I suggest the first one called "the movie fix"

the movie fix
I did some searching on the solution with the movie files mentioned below by FBmantis. I have read from several forums that the dice.bik movie is a main culprit. I had previously removed the movie for faster loading. Many have reported success by putting the movie back or using the following progam to put the movie back in its proper place.

avialable from 2 locations:
http://battlefield2.filefront.com/fi...TTAB_Fix;74863

http://planetbattlefield.gamespy.com....php?id=109647


This file installs a version of the dice movie. You don’t need to have the dice movie, it comes with the file. I have checked the files in both locations listed above for viruses. Both versions are identical and virus free. The above files are .exe installers which put the movie where it belongs.

After installing this fix. I can alt tab, even while loading a map. The game does NOT need to be at the same screen resolution as windows. So far it is flawless. Only problem is I have to sit through the dice movie every time I load up the game.

I have read that even if you have the movie installed, removing your movie and replacing it with the one in the above file will fix the alt tab problem if you have it.

An alternative fix:
1. screen resolution must be the same as windows. if you play at a different resolution than windows is at, change your windows resolution to match.
2. alt tab once before joining server, then alt tab back in.
3. join server. you should be fine alt tabbing now.
-the drawback to this alternative fix is that you need to have windows be the same resolution.