Remembered mine post: “Dumb Airone”? Sincerely on this thing I have risked that the brain went me in baby food, but at the end… Victoria!  And sapete qual'era the problem? “Fottuto” (passatemi a term, if other I do not vent me) IRQ conflict. Evidently the installation of the driver ati qualifies “something”, has not still understood what, that it enters in conflict with my audio card onboard, ill-famed Intel ICH5 Realtek ALC202:

0 [ICH5]: ICH4 - Intel ICH5
Intel ICH5 with ALC202 at irq 20

The solution? It has been enough to insert irqpoll pci=routeirq in the line of boot of the /boot/grub/menu.lst rows.
Ravvio and, music for my orecchie!

It marks it near: