Ok this happened to me while I was in closed beta. But now its worse my UI to login is flashing every color of the rainbow and is slowing my computer down but when I click CTRL+ALT +DELTE the UI stops flashing when I get off the task manager the client crashes.
Hello could you post a screenshot and your system specs.
Error
Sounds graphic card related, post your system specs as Error has mentioned.
If it is artifacting it means your hardware can’t handle the game (But that will be determined when you post your specs).
Try setting the game to compatibility with WinXP SP3 and see if that helps any.