Same thing just happened to be, i havent placed in about 2 months though, since the new HUGE update. I went to play and it was downloading. Than AVG says i have a trojan, or some sort of virus. So i accept and let it get rid of it. Than i go to open my Guildwars shortcut and it says its invalid. It isnt on my desktop anymore and i have to reinstall it all over again. Pretty upset as i dont get a lot of free time to play.