Social network / domain access problems

I have had a problem loggin on to my yahoo messenger and other social networking application ever since my upgrade to leopard v.10.6.8. It was reported to me on other discussion sites that some networks have had issues with several newer versions of Mac OS...

To explain my problems further... when I try logging onto Yahoo for instance.. It goes on to log and the waiting icon just keeps rolling forever.

Some sites I try to view thrue either Chrome or Safari, I get this error message : Safari can't open the page "http//.whateverthedomainname.com, because the server unexpectedly dropped the connection. This sometimes occurs when the server is busy. Wait for a few minutes and try again.

Now this message has been coming in from several internet pages and has been going on for several days. So its obviously not a domain problem.

I have tried re-installing my applications, emptied cache, resetted safari, and so far nothing.

Thank you for your input.