All is not well in Hyboria. It turns out that the early access offer which allows you to start playing Age of Conan already on May 17 was a limited offer, and is sold out. That left a lot of angry customers holding a valid pre-order key, but without early access as promised. The reason given for the limited number of early accesses was that the Funcom servers couldn't handle more people downloading the 14 GB client. Funcom could have solved that easily by offering people who already had one of the various beta clients installed a way to patch that client to the release version. But no, that wasn't possible, you had to uninstall the beta and download and install the huge early access client again.
Next problem was that the Funcom early access downloader resulted in many people having corrupted downloads, and receiving "ERROR: Filesize incorrect" message when installing the game, leaving them with a non-functional client installed. That can be fixed, but you need to know how to do it: Go to the directory where you installed Age of Conan in, find the SimpleConfig.exe program, and run it. Click on the Verify / Repair button, check the repair checkbox, and start verification. That verifies all the Age of Conan files, and downloads correct version of corrupted files.
Once you got all files in order and start the game, there is a good chance that you will only see a black screen. In that case you need to stop the program, and run SimpleConfig.exe again. This time go to the graphics tab and check whether it is set to DirectX 9 or 10. If it is 10, it won't work, so set it to 9. If the screen remains black, try changing the resolution in the SimpleConfig.exe program to something lower. That should fix the problem. Once you see something, you can change the resolution back to high with the Settings button when Age of Conan is running.
I got the early access client downloaded, installed, and fixed, but it took me two days to do so, including several visits to the AoC Technical Support forums, where I received some good solutions from other players, but never saw a Funcom tech responding. Needless to say that up to now I'm underwhelmed by the technical excellence of Age of Conan. It isn't as bad as Funcom's last release, Anarchy Online, but still far from smooth. And from a marketing point of view having early access only for a limited number of preorder customers sounds like a rather bad idea to me.