It may be a HOSTS file problem.
Look also for a file named HOSTS (no extension, could be hidden) rename it
OLDHOSTS
Check for parasites.
Dealing with Unwanted Spyware, Parasites, Toolbars and Search Engines
http://mvps.org/winhelp2002/unwanted.htm
--
Henri Leboeuf
Web page:
http://www.generation.net/~hleboeuf/index.htm
"Jim" <(E-Mail Removed)> wrote in message
news:8ce901c40511$488e6150$(E-Mail Removed)...
> Many of the computers at my company can no longer access
> anything from Yahoo. I know that we are not blocked
> because some machines can still access it. This also
> includes Yahoo messenger. Any suggestions
>
> Thanks
> Jim