CD KEY WONT WORK

Hello,

I am trying to play BFBC2 after being out of the game for a long while. (Year or two)

I recently re-install it on my PC (win7)

Once I login I am met with the product key code screen, I input my CD key code only to get the same error code over & over.

" The register code is already in use. " 

I have no clue how to bypass/fix this problem. I have the Original CD & KEY CODE so why is it saying that it is already in use? 

Even though I registered it once upon a time... Why am I not just able to login like before?

To make it simple.. How the heck do I register it on my PC & get back in the game? 

Regards -