I FORGOT THE SECURITY OF MY NOKIA C7... i need help to unlock it!

Kindly refer to AniaC's post to contact Support, reset security code cases have to be handled outside of the F-Secure Community.

http://community.f-secure.com/t5/Mobile/Forgot-lost-your-security-code-Read-this/td-p/7439

For alternative way to unlock your mobile, refer to the following post:
http://community.f-secure.com/t5/Protection-Safe/f-secure-mobile-password/m-p/11397#M2688

Thanks.