I am in the same boat you are. About a week ago, I started getting lag in game which I have never encountered in almost a year. It got progressively worse to where the launcher even was taking 15 minutes to get to play, I hit play and get a black screen. I have spent the past week reinstalling the game, updated everything, messed with settings/config files, and watching dozens of youtube videos tweeking everything. I still get the black screen. I was able to get in game yesterday once, but the lag was so bad, I couldn't do anything. I disabled firewall/antivirus didn't work. Weird thing is I am able to run and play ESO and LOTRO fine.