So I assume you have a to patch UT before you install INF right? I found my UT disc, I am going to give it a try. EDIT: Hmm... I'm installing UT right now but I have no clue as to where the CD key is, I don't see it on the disc or it's case, and I don't have the box or manual anymore. Hope I'm not screwed.
As has been said, no CD key is required for UT. I am installing INF right now and the package asks if you want to install the 436 UT patch before any other files, so after installing UT from the disk, just run the exe and everything you need should be there.