maybe the cd key is still in one of your q3cdkey files? Rr else... recover diskfiles. And if that's impossible then you can always try to guess your old key, using a day or two.
I dont have my own box, I gave it a friend to pay off a debt, harddrives have been wiped. Ive been trying to remember my key, Ive got half of it, I cant get the ending sequence right though.