I just found a wonderful windows repair tool.
I had a rootkit infection and while it removed the virus, it trashed my system,
specifically my windsock stack, making some programs able to access the web
and others only when run with elevated/administrator privileges. (that is the diagnostic)
Try Tweak.com Windows Repair.
A big pile of command scripts and console programs that addresses narrow permissions issues
that plague windows and produce strange almost random appearing failures.
It is misnamed. They have a permissions repair tool. It also fixes
reparse points. And you need to check your disk file system security descriptors.
Then you can try the Windows Fix-Its gizmos.
Check your windows authentication. You may discover windows can't verify your key,
and determine your copy of windows is counterfeit. You need to verify your windows key
to do windows update servicing. It depends on lots of other things, including a working
permission settings in the windows net tcp/ip stack.