I have a network of 2 desktop PC's. One is a new Compaq with an onboard network card and the other is an unbranded one with a seperate Realtek card. They are both connected to a Philips wireless router but the wireless is not used. They will work perfectly one minute and then the next time the Pc's are turned on one of the cards will have disabled itself. You can re-enable it in device manager and they will connect fine again. The only software running is McAfee A/V. Can anyone explain why this keeps happening?