I had exactly the same problem, and even tried with a fresh installation of Windows 7. The BSOD error was BUGCODE_NDIS_DRIVER. It also prevented windows restarting and required running the repair utility. I had the same problem with Zonealarm, but have found Kaspersky Internet Security Suite 2010 v9 works fine, so I am using a trial version of that for now. Let's hope McAfee sort the probelm soon.