Login problems
Try running as Administrator?
Try turning off any 3rd-party programs, such as those that come with graphics cards?
Try a -repair of the client?
Try Googling for those threads here in the forum that address this issue? I can’t remember the ‘fix’ for it.
Good luck.
LOL: https://forum-en.gw2archive.eu/forum/support/support/Unable-to-initialize-3D-output-Game-wont-launch-help/first#post243641 (Look at the date!)
Edit: Okay, this might actually solve your issue if you are using an AMD graphics card: https://forum-en.gw2archive.eu/forum/support/support/Direct-X-9-issue/first#post6598875
(edited by Ashantara.8731)