No sound!

If I minimize the screen and it turns off (screen sleeps) when I wake it up I've no sound on Guild Wars! I've sound everywhere else and it doesn't return until I'm completely out of the game and return! What's the deal?

It usually happens when I'm mid-mission and so abandoning the the game to start a big mission again is just daunting!

gw will mute the sound if it's out of focus or minimized but should have it back once you restore the window. Try unchecking this option.

It's probably some sort of driver conflict, so the first thing to do is to update Windows and make sure you have the latest drivers for the chipset, sound, and video.
If that doesn't help, then stop minimizing the screen in the middle of a mission. If there is some reason that you need to leave GW to do something else, simply leave GW running - in a Window if you need to do something else on your computer.