I have got one of my client has got a simple office network with three PCs (2 desktops A and B and one laptop C,,,,,all of them have got Vista Home edition).
Those desktop are connected through a modem router.
He bought a computer B recently and it has a Trend Micro Internet Security installed on it,,,,,,,a USB printer is connected to this B PC to be shared with A and C.
The other two PCs have not got Trend Micro Internet Security (I am aware of security implication , this is not the issue of our thread)
the printer is shared but A and C can not ping and can not print.
I am sure that the problem lies with the Firewall setting for Trend Micro Internet Security, because when I shut down it from A and C I can ping the B and I can print ,,,,while when Trend Micro Internet Security is running I can not ping B and I can not print.