CD Key Problem

[legacy-Tsetsuki]

I have a problem and was wondering if anyone else was having the same one and had any insite on how to fix it. I just installed UT2K4 on my new PC, and it worked fine in the install. Then when I attempted to play the game, it asked me to put back in the DVD (I have the DVD SE), so I did. It then told me my CD key was invalid, even though it is exactly what was given to me and was accepted during the installation. No matter what I try, it doesn't work. Anyone have similar problems?

-Tsetsuki