I haven’t any character yet. Today I first chose Darkhaven server, then I couldn’t see screen again when i tried to login. After 8 hours I found solution, also for beginners like me. First I cleared Guild Wars folder in Appdata. Then I wrote these commands on cmd:
(you can google if you want to know what appdata folder and cmd are)
-ipconfig/flushdns
-ipconfig/release
-ipconfig/renew
Now I can see the character creation screen.