Windows 7: Can't access Yahoo Mail after upgrade

Has anyone else had the problem of not being able to access their email (random ones) or Yahoo! Mail's newest configuration after you upgraded to Windows 7?

I have IE8, Firefox's latest and Safari and none of these browsers will allow me to access my Yahoo email, except in "classic." I spent several hours on the phone with Sony (I have a Vaio and the Windows 7 upgrade was free), and they couldn't understand why this was happeneing in each of the browsers. I sent an email to Yahoo, but I haven't heard back from them. The tech I talked to at Sony said that quite a few people had called in with the Yahoo issue. Any thoughts?

What happens that prevents you from accessing Yahoo?

For some reason when I go to Yahoo mail, it will not open in the new format. It will only allow me to see my mali in the Ckassic format, and even then, it won't open some emails. This happens in each of the web browsers I tried.

Check your Java settings. You may also want to give Google Chrome a try.

Java is up-to-date as well. I had also looked at uninstalling IE8 and going back to version 7, but IE does not show up in my Program file. Any suggestions?

When I try to send mail in Yahoo, I always get 'unexpected error' . Still getting incoming, but cant send. Tried it in Firefox & it works fine, just seems to be IE (8.0.7600)