http://gbatemp.net/index.php?showtopic=132872
I just wrote a guide on how to change the battery without soldering. Try it out if you want, or get your classmates to help you solder.
I purchased my EZFlash V 3-in-1 expansion just over a year ago. All of a sudden, my GBA games stopped saving. They played fine, but refused to save. I searched all over and finally concluded that my battery must be dead. The battery is necessary to hold a game's SRAM save.
When your battery...