tail section moving

on every plane i fly ,the tail section keeps moving from left to right evenif i set the weather or not . is there any thing i can do to stop this. all my freinds that have the fs2004 are not having this problem.please help

1. Verify, by pressing Shift+Z, that the wind is 000/00 (no wind).

2. Usually, the prop planes yaw due to forces created by the propellors.

3. In the "Realism" menu, verify the "Autorudder" option is disabled.

4. Verify that none of the left or right brakes are pressed.