Sounds like you need to adjust the proportional on the 4-in-1. It's the inside dial closet to the motor plugs. First turn the gain dial (other one) all the way off (IIRC counterclockwise). Unplug the battery, adjust the dial, just a hair at a time, and then start up. Check it and if it's still rotates, or gets worse, repeat until it holds. You have to disconnect the power each time and make sure you don't move the heli until the 4-in-1 initializes fully. A lot of people have trouble with the gyro because they plug in the battery and then set it down or move it in some way before the 4-in-1 engages. Once it has power, it shouldn't be moved until the gyro locks in. After you get the proportion set, you can adjust the gyro. Usually somewhere around 90-95% is about right. The gain can be adjusted with the power connected.

dignlivn--I tried cmassa's method twice and figured it wasn't worth it. Too easy to break again. I use the same one Doug (djdavid) has.