Windows 7 - Problems with headphone virtualization

Recently I've been having a few audio problems...
Mainly it feels really random, sometimes the sound in one application doesn't work, etc. For example, I have Windows Media Player open playing something, then I open up a game and the game has no sound. Maybe Windows sounds (eg. Start navigation) don't play when they should.
Or sometimes it's the other way around and I might have sound working fine in another problem, then when I open a file in Media Player it fails and says "Windows Media Player has encountered a problem playing this file". Sometimes if I keep trying to open that file over and over again it eventually works and has sound. Once or twice the sound has gone crackly instead of cutting out completely.
So in short the problem is really random.

After some experimentation I found that disabling headphone virtualization in the Realtek HD Audio Manager fixes the problem. But I can't live without headphone virtualization... anyway, the problem has only started happening recently so it should work properly. I tried installing the latest Realtek drivers but this caused a heap of more problems. System restore didn't fix the problem either. Can anyone shed any light on why this is happening?

try disabling this from the playback device properties in the volume control if it is enabled:

Okay, thanks I'll try that
Marking this as solved in the meantime