the pc starts by itself in the middle of the night and also starts by itself when the phone rings.
Disable "wake on LAN" in the BIOS
'can't find floppy drive' message,
Disable "floppy seek" and "FDC" (floppy drive controller) in the BIOS
'Via OHCI Compliant IEEE 1394 Host Controller'
Does not sound like a sound chip its a firewire controller "The VIA IEEE 1394 OHCI host controllers offer a high-speed serial connectivity. The guides below describe how to mount a 1394 SBP-2 (Serial Bus Protocol 2) compliant ATA storage device with those controllers."