I have just spent quite a bit of the weekend trying to resolve an issue with a friend's computer. They had done a factory restore on it, to clean it up and from the moment it re-started it would not access the net.
So they brought it over to my place, set it up and sure enough it wouldn't access the internet. We tried LAN cable, wireless etc and nothing. The Windows 7 troubleshooting would tell us that the network was running but that for an 'unknown' reason could not access www.microsoft.com
I tried everything I knew to resolve it and it had me scratching my head until whilst looking at advanced options in Windows firewall, I found that all connections were being blocked, but I could not turn that off. A google and I found the answer. Norton's Internet Security was part of the factory restore, but even though it had not been 'activated' and set-up on the computer, it was controlling aspects of the system. Whilst I was trying to resolve the connection issue, Norton's popped up a couple of times asking me if I wanted to install it and that I did not have any active security on the PC. I just closed it down, cause once I resolved the internet connection, I had planned to put AVG on this computer.
So I uninstall Norton's and straight away the internet connects...hmmm
Norton's wasn't my favourite set of applications before, but now that I have found that even if it isn't set-up and activated, it takes control of some aspects of a computer it is on, then it has moved to being even further down the heap of junk applications.
Glad I solved the issue, but for an application that wasn't even activated, from factory, Norton's is insidious and I would never recommend it to anyone.