I am also at a loss. I was playing on the trial for 8 months. Just purchased the complete collection two weeks ago. Last week, I started noticing lag which I never encountered before. It progressively got so bad, I couldn't log in. I spent a few days doing research and literally tried everything. I unistalled the game to start over, and am attempting to reinstall it.
Now, the downloader will start downloading around 40 - 50 per second. When I get a quarter through the download, it drops to 2-5 per second until it say unknown and freezes. Now, the patcher will take 5-10 minutes to even open. I turned off virus protection and firewall, updated all my drivers, lowered ping, lowered clock speed. ESO and LOTRO work perfect still on my PC (Alienware) with no issues. I literally am at a loss and don't know what to do.
Lastly, I only received a directx crash once the day before I could no longer get on.