How can I log in to my Guild Wars Account automatically when I launch the Game Client?
You have to add some command line arguments to Gw.exe when you start the game up.
The two that you need to add are
-password. Have a look at this link for more complete details:
From the link:
Instead of using the command line, you can execute switches directly from your Guild Wars shortcut:
1. Right click on your Guild Wars shortcut and select 'Properties'.
2. In the 'Target Area' field you will see the location of your Guild Wars executable file: "<...>\Guild Wars\Gw.exe"
3. Write the desired command line arguments after the quote marks, each beginning with a space: "<...>\Guild Wars\Gw.exe" -perf -windowed
Create a shortcut to the gw.exe or edit its properties and add following options after “C:\Program Files\Guild Wars\gw.exe” -email mail(at)provider.end -character "Name Of Your Charakter" -password qwerasdf
Be aware: Your password is saved in cleartext!
Other command line options can be found on GuildWiki