Hey.. just registered to help with a topic... apparently I have to say HI first?
I had a client's laptop infected with What MS Sec Essentials was seeing as W32/Patched.AO - and had infected c:\windows\SysWOW64\dnsapi.dll.
Apparently this is something new making the rounds in recent weeks. Basically, it was killing and re-routing the DNS. I could PING Google and other sites- but no DNS was resolving.
Multiple restores and adware removals later- I still could not connect. So- I just copied c:\windows\SysWOW64\dnsapi.dll from a working Windows 7 unit to the non-working...and voila... connecting up fine now, even after reboots. This is assuming you have removed the infection - in my case - a variant of ShopperZ malware.
Spent a couple of hours facetime on this... thought I might toss this out.
I registered just for this...lol