I was playing the base version of the game but today I purchased the Morrowind upgrade. I installed the new client. Allowed it to update. Now when I press play it says that "ESO has stopped working." "Close program."
Some of the game files may not have updated correctly. Try running a repair once or twice through the launcher and see if you can then launch ESO again. To repair the game client, open the ESO Launcher, click Game Options, and then select Repair.