On battlefield 2, i unlocked a weapon but i cant use it. Help!?

On battlefield 2, for the PC, i am a corporal and i unlocked the next special forces weapon. Only thing is, im not able to use it. How do i change weapons from special forces you start with to the new unlocked one?]





Thanks so much, whoever has the right answer gets best answer. not first answer.On battlefield 2, i unlocked a weapon but i cant use it. Help!?
When you are in the game, you click the up/down arrows next to the gun you are selecting, it will switch the guns, It will be a yellow up/down arrow if you have a selectable unlocked gun.