My computer is on Windows XP. The game seems to randomly work or not. One day it will work perfectly fine, but then the next day it may not load at all (it sticks on the "Connecting to ArenaNet" screen). The problem (when it arises) seems to fix itself by the next day, but there have been times where the game won't load for a coup,e days at a time.
I was playing early today, but when I came back a couple hours later, the game won't load.