its a command line arugment, right click on your windows shortcut,in the target area field you will see something like ''C:\program files\Guild Wars\Gw.exe''.If yours is starting WMC when you close guild wars then it probably says something like -mce at the very end of the shortcut, all you need to do is delete anything after the exe'' and it shouldnt happen anymore .Look here for more info. http://wiki.guildwars.com/wiki/Command_line
its a command line arugment, right click on your windows shortcut,in the target area field you will see something like ''C:\program files\Guild Wars\Gw.exe''.If yours is starting WMC when you close guild wars then it probably says something like -mce at the very end of the shortcut, all you need to do is delete anything after the exe'' and it shouldnt happen anymore .Look here for more info. http://wiki.guildwars.com/wiki/Command_line