Itune sound is stopping itself then come back

Hi,

I use Itune 8.1.. on a apple macbock with XP pro.

had no problem till today
did not change my configuration, no update, no new programs

When I use itune, the sound is malking some "tic" "blick".. like on a old tape or disc (or intersideral "zic" there is 3 or 4 diferent noise).
After some sec or min after one of these sound, the itune sound stop but the song continue to play. the small noise are still there but no music
If I pause the song and push agin on play it's ok, If I start a new song it's ok.. some sec and no sound one more time. song are dowloaded from Itune or compressed from CD.
The same with only flu radio.
same for podcast .


It appen local on my computer and remote on airtune as well.
Windows media player and VLC are ok

I did try to

-Repare itune
-Uninstal itune and quick time
-Uninstall and erase all folder and regedit I found
-uninstall and reinstall via apple update
-restore to yesterday
-uninstall then reinstal itune 8.0 (not passible to open because of the data -library newer) then reinstall 8.1

Still the same..

Is somebody as a solution for me without formating my computer?

Thanks