Unable to remove Google Redirect virus despite full NIS & NPE scans & online support

This is very frustrating - I've read thru other posts and see that fixes need to be tailored to the individual PC. I've been working with Norton online chat support over the past 2 days to remove this virus and nothing works. Or...fixes appear to work initially, but then an hour later it's back again.

I have Windows7 SP1 64-bit, NIS 2012 w/all updates

Everytime I try to search in Google it redirects to that bogus website 8.26.70.252 or other fake ad URLs. It's especially bad in IE9 - I can't even use Google there anymore.

I've switched to Firefox, and haven't come across it  (yet), but know it's still lurking.

 

NPE scans always return "No risks"

Full NIS scans did show a few Trojan.Gen issues that were 'fixed', but as of now only show "no risks" except for cookies

I also ran NPE from a NBRT boot disk, also "No risks" detected.

they (Norton Support)  had me download "Norton DNS", altho I'm not sure what it's supposed to do.

 

I'm a novice when it comes to technical issues, so really lost here as to what to next. Help?