I'm trying to run League of Legends through PlayOnLinux on ubuntu 14.04. Everything worked perfectly, until the game would start. I can heard the game noises, but then the game would crash. Trying to figure out the problem I clicked emulate a virtual desktop and run the game again. Now everything seemed to be working and I could run the game smoothly without problems. So what would the difference be between emulating it in a virtual desktop and not doing so, in order to pinpoint the problem...
SnapOverflow
Emulate a virtual desktop is an option in Wine to run applications contained inside a window, which pretends to be the desktop of Windows.
Emulate Virtual Desktop creates a separate window that acts as a desktop for launching games. Since it matches the resolution of your Linux desktop to make games appear full-screen, it eliminates the need to change the resolution manually using the game's config files.
In your case, the resolution of LoL may not have been set correctly and that is why although you could hear the sounds, the game UI never appeared.