I thought this issue was resolved, but my last post had many people saying that people still couldn't play. I'm assuming that the black screen after clicking play is the reason?
Here is a fix for the black screen after clicking play on the launcher. Seems to effect the same people who had the greyed out play button during beta and launch.
Switch these values in My documents-Elder scrolls online-live-Usersettings.txt from -1 to "0". If they are not in your settings which is the problem for some, take my already fixed usersettings file or add in the lines to your usersettings. My documents-Elder scrolls online-live replace usersettings with this.
SET RequestedNumJobThreads "0"
SET RequestedNumWorkerThreads "0"
(If "0" doesn't work for the above, change them to "1" also fixes it for some)
P.S. If you are adding them in manually instead of replacing the file attacked, you also have to add the following lines to your usersettings.
SET MonsterTellsEnabled "1"
SET DisableFXPrecaching "1"
SET PreferExclusiveFullscreen "0"