Today, I am going to show you some solutions to fix your problem of being unable to access your webmail. You may still be able to access other web sites successfully, but for some reason you cannot access your webmail account. If you cannot get your webmail account to work and get a message that "This program is not responding", with Microsoft Internet Explorer, you can try downloading, and installing an alternate web browser.
You can change your web browser to Mozilla Firefox for example. Another possible fix is for you to select a "Tools" menu option in Internet Explorer, and then select "Internet Options". In Internet options click on a "Delete Cookies" button, and let it delete your web browser cookies.
Next, click on "Delete Files" button, and let it delete your temporary internet files. Finally, click "OK" when an hour glass disappears, and Internet Explorer is finished deleting all your files. Close Internet Explorer and reopen it.
If that doesn't fix that problem, you can try to see if you might have more than one instance of iexplore.exe running. You can hit your "ctrl" "alt" "delete" keys at same time, which will open up a window. In that window select "Task Manager".
In windows task manager look to see if more than one iexplore process is running. Click on a "Processes" tab, then click on an "Image Name" tab to sort those processes alphabetically. Highlight any and all iexplore.exe processes, and click on "End Process" one by one.
After you killed all those iexplore.exe processes open up Internet Explorer, and try to access your email. If your trying to access Yahoo webmail you may receive "Done", and "Opening page about:blank" messages when trying to access your Yahoo email account. You can browse to a troubleshooting web page for Yahoo mail.
You can follow all those troubleshooting steps you want to but "Switch back to Yahoo Mail Classic by opting out of Yahoo mail", and "Check your email in Yahoo Mail Classic" will hopefully get you into your mailbox successfully.
You can try accessing your email from a generic Yahoo page. It's pretty basic, but hopefully you can read your email for now, until you find a solution where you will be able to use Yahoo mail classic, or a newer Yahoo mail.
If you by chance have any toolbars like a Yahoo toolbar installed or Google's toolbar, sometimes those toolbars can create problems with certain web sites. To remove any problematic toolbar(s) you would go to "Start", then "Control Panel", then "Add/Remove Programs" in control panel. You could remove any toolbars ie. Yahoo toolbar, and try accessing your email via a following link, and then you can bookmark that login page to access your email.
Another possibility would be to login to your email via Yahoo Webmail, and then either clicking on "mail" at very top left corner, or hovering your mouse over a mail icon under "Personal Assistant", and then waiting for it to list your emails. Once it's done then click on an email to try to open it. If you are not having any other issues like this with other websites, then I think it's possible there is a problem with your specific email account on Yahoo's servers, which does occasionally happen.
If you have another Yahoo email account or a family member has a different Yahoo account, you could try signing into that account to see if it's specific to your account. Most of these fixes for your webmail problem are specific to Yahoo webmail, but could certainly be used as stepping stones for other webmail providers.