Email Functions Suddenly Don't Work

I have Yahoo Mail via Att.net. I noticed that the Yahoo Mail website has a new design. Now I'm having trouble with several emails features. Examples: I can't check an email address because the Contacts List won't come up when I click on the icon. When I try to reply to an email, I can't reply because nothing happens when I click on the Reply button. When I try to search previous emails for email addresses or anything else, nothing happens. I restarted my laptop and it doesn't help the situation. What can I do to restore all of the missing features in my Yahoo Mail? I have pending email messages I need to reply to and I can't. Thanks for your replies.