Network disabled while sharing files from Seven

i got this problem, i have some folder shared on my local network, if any other pc using different OS ( vista, xp and seven too) try to take some file my computer network will became disabled. i have to restart my pc to restore it. even if the others pc listen or watch some multimedial file that i share my computer will disconnect from the network.

I have windows Seven Ultimate 64 bit, my lan card is an integrated atheros L1 gigabit ethernet controller.
I've tried to share some files on my mother's laptop (that has seven home premium 64) and take that files whit another pc ( not mine ): works perfectly. when i tried to take that file whit my pc, my network card disabled...

Thanks for your help!
and sorry for my bad english... i'm italian :D

This website is not affiliated, owned, or endorsed by Microsoft Corporation. It is a member of the Microsoft Partner Program.