I solved this problem by installing winpcap software. This software contains the NPF.sys driver. This solves the problem. I could not find out if NPF.sys was a Windows 7 default driver. It was never on my system and it was not loaded from counterfeit software unless Tigerdirect is now selling counterfeit software. I had previously posed this same question on several other forums and was given basically the same answer everywhere. So I still do not know if NPF.sys is installed on other versions of windows 7 software and just not on w7home premium OEM.