Nvidia nforce networking controller stopped working

I recently installed an ATI Radeon HD 3400 series video card into my hp pavilion a 6130n. When I did that my on board Ethernet card (NVIDIA nForce networking controller) stopped working. I installed a wireless network adaptor and it works fine. I removed and replaced the drivers?. No joy. In device manager it says the device is working properly. If anyone has any ideas I would appreciate it.