HP Compaq 6200 Pro SFF I5 DESKTOP (XY111ET) RESTARTS 30 SECONDS AFTER SHUTDOWN

HP Compaq 6200 Pro SFF I5 DESKTOP (XY111ET) RESTARTS 10-15 SECONDS AFTER SHUTDOWN

MODEL LINK:

http://h20565.www2.hp.com/portal/site/hpsc/public/psi/home/?cc=it&jumpid=reg_r1002_itit_s-001_title_r0001&lang=it&sp4ts.oid=5037900&ac.admitted=1487060462261.1123376534.492883150

Hallo,
as I wrote in post subjet, I have a desktop pc (6200 sff)  with this issue.
It seems that something is enable in bios, that allow pc to start if network traffic is detected.
So if I regulary shutdown, the pc turns off, but after 15 or 30 seconds, it restarts itself.

I think it could be "wake on lan" but I'm not able to find this setting in bios menu.

Someone could help me?

Thank you.

Marco