Can no longer connect to internet

I started getting messages in IE when I tried to navigate to any website that
I had to be an administrator for that installation. To solve this, I turned
off the option to require administrative authorization for changes to the
computer.

When I did this, I lost connectivity altogether. I went back and changed
the setting, but to no avail.

I've had the computer about 3 months. I'm connected directly to a cable
modem via ethernet.

Any help would be greatly appreciated

Dave