Alsa sometimes working, sometimes not - drives me crazy

[m.s.w]

Hi,
I have two soundcards: on-board Intel-HDA and PCI: SoundBlasterLive!.
I got them working perfectly until I had to reinstall Gentoo becouse of HDD failure.

Now I have installed everything back as it was before. I have two users, my wife, and myself.
Strange begaviour goes like this:
- I login as myslef and I start KDE4 session. I have sound working on all soundcards (tested in KDE Multimedia device managers)
- Sometimes even if in KDE Multimedia device manager test sound is played, I don't have sound in other applications.
- I log out from the KDE session and I startx with my prefered WM which is fluxbox. I do not have any sound. I can't hear anything playing youtube, nor playing any audio files with aplay.

If after boot I log into my wife's account and I start KDE, I do not have any sound.

BUT, sometimes, when I boot the system and I log into my account and startx with Fluxbox - I do have sound!

One thing that happens all the time is that my wife has no sound at all.
We are members of "audio" group. In fact we are members of exactly the same groups.

I don't realy know where to search for answers.

I have alsa built-in kernel. Kernel 2-6-31-r5 (but the same was for r4 and r3)
KDE 4.3.3
Do you have any ideas?
_________________
Mark Twain said it best:
"If you have to swallow a frog, don't stare at it too long!"

[truekaiser]

i would have to say it might be because of a misbehaving application rather then alsa, dmix has been enabled by default for a while now on alsa and the only programs that cause problems like you describe are ones that try to grab the hardware directly rather then talking to alsa via alsa-libs.
_________________
"My father rode a camel. I drive a car. My son flies a jet-plane. His son will ride a camel."
—Saudi saying
Too late to do anything about it, so just sit back and enjoy the fireworks.

[m.s.w]

Thank you for your answer.
It might be true what you said, becouse I did a little more research and I know now, that after clean install samba works OK until I start KDE. After that it tells me that the audio devices he found are switched off and asks me whether Kde should swithc them off permanently. I say "no", but it doesn't change anything - there is no sound in kde, and no sound at all in other WM.
One more thing is that my wife when she was asked about kde switching off audio devices permanently she said "yes".
Is there a way to revert her answer?
_________________
Mark Twain said it best:
"If you have to swallow a frog, don't stare at it too long!"