Lost Doom3 CD #1 - can't play game without it?

I have a legal copy of doom 3.  Got the box, serial, and other 2 CD's right

here.  But I lost CD1 and now can't play the game.

I tried downloading a copy of Doom 3 I found on a torrent but it's not 
working.  Any suggestions??

Thanks

wolfereeno at yaho