Go to the folder you have the game installed in... in my case it's:
D:\Games and Apps\The Lord of the Rings Online
In that folder is another called BACKUP, copy all of the contents of that folder and overwrite the files in your main "The Lord of the Rings Online" folder, try re-launching.
That worked for me.
Another option would be to go back to an older restore point and restoring back to that time (from within Windows).
[center]Irin r8 Hunter // Arngar r8 Burg // [b][color=red]Akthuri r15 LM[/color][/b] // Vishus r5 Captain[/center]