Network drivers wont install i keep getting this error invalid access to memory

My son ran some program that he didn't know what he was doing and now there is no Network access. When I tried to reinstall the drivers an errors pops up stating that the drivers couldn't be installed due to "Invalid Access To Memory Location'. The networking card is an Intel 82566DC-2 Gigabit Network Connection Adapter. The Networking card is part of the Motherboard. I have the original drivers but they will not install due to the "Invalid Access To Memory Location". Anyhow my son went and bought a new networking card, and it gives the exact same error. I tried uninstalling the networking card in the device manager, but when the hardware is reinstalled, and the drivers are about to install it gives the same error. Can anyone please help the computer is a Dell XPS 420 with 6 gigs of RAM, an Intel Core 2 Quad CPU Q6600@2.40GHz Also in the Device Manager everything under the Heading Network Adapters has a Yellow Triangle with an Exclamation mark in it. I know that this means that there is an error somewhere. Any help will be greatly appreciated....I also want to add that when I checked the Netgear GA311 Network adapter card in the Device Manager it says This Device is not working properly because windows cannot load the drivers required for this device (code 31). I hope this helps Thanks again for any help that is offered