If you downloaded it digitally and it's a fresh install the game is trying to download every known update... which indeed takes a long time. This can lead you to thinking its stuck on 0% (I remember me thinking that a long time ago when I had this problem).
What you can do is use the
"-image" command line argument to force the game to download every known update all at once (this usually takes a decent amount of time) instead of having the game download as you go... which is rather annoying.
To do this navigate to the file where you installed Guild Wars. The default location should be along the lines of "Local Disk (C: ) > Program Files > Guild Wars"
Locate "gw.exe", right click it, and create a shortcut on the desktop. Once you have the shortcut to "gw.exe" on your desktop right click it and go to "properties". In the "target" box you should see something along the lines of this: "C:\Program Files (x86)\Guild Wars\Gw.exe" [quotes included]
In the target box add a [space]-image at the end of the command line. So now, it should look something like this: "C:\Program Files (x86)\Guild Wars\Gw.exe" -image. Note that there is a space after the last quotation mark and the -image. Hit OK.
Now double click your shortcut and the download should start... As stated before this may take a good long time. I usually let mine run overnight or while I'm out doing something else.
This should fix your problem, if not then I'd wait for someone else to come along and help because I have no clue past that.