You do /not/ have to install /any/ applications to use /any/ DSL service.
What "browser" did SBC/Yahoo supply? Is it an Internet Explorer version
(which is why I asked about IE Help>About>Version)? While you're at it,
look at IE Help>About>Update Versions, too, in the SBC/Yahoo browser, and
post what you find. (That's what "javascript:navigator.appMinorVersion"
would report.)
The IE browser you /did/ run it in is woefully outdated and much-less secure
than what's available now. Using that browser, go to Windows Update and
install recommended updates and patches. To assure a clean install, your
anti-virus application should be disabled and all other running processes
closed before going to Windows Update and when downloading/installing from
any MS page.
IIWY, I'd uninstall everything SBC/Yahoo-related (via Add/Remove Programs)
including the "SBC/Yahoo browser". To assure a clean uninstall, your
anti-virus application should be disabled and all other running processes
closed at the time. Reboot afterwards, then...
Check your system for "hijackware":
Dealing with Hijackware
http://mvps.org/winhelp2002/unwanted.htm
http://www.mvps.org/inetexplorer/Darnit.htm#tshoot
http://aumha.org/a/parasite.htm
http://www.merijn.org/cwschronicles.html
You *must* seek updates for Ad-Aware, Spybot, etc., before each and every
use, even "right out of the box". But even then, they can't catch
everything. When all else fails, HijackThis
(
http://www.merijn.org/files/hijackthis.zip) is the preferred tool to use.
It will help you to both identify and remove any hijackware/spyware. **Post
your files to
http://forums.spywareinfo.com/ or the Spyware forum at
http://forum.aumha.org/ for expert analysis, not here.**
Also update your virus definitions and then run a full system scan. From
now on, do both daily.