"Hi Janet D. I was having the exact same problem and finally figured out the problem tonight. The Yahoo POP3 server was telling my computer that there were 19 new email messages to download, but in reality there were 20 new messages. This was causing outlook express to fail with the 0x80004005 error. Here's what I did to fix the problem: I logged into my account on the yahoo website and went to my email page on the web. I then created a new folder called "temp" in my webmail account. Then I moved all my new emails from my webmail inbox to the new "temp" folder. Then I moved all those new emails right back to my webmail inbox, and that fixed the incorrect count. After that I ran outlook express and sure enough, it downloaded all my messages with no problems.
Just note that the 0x80004005 error is used by Microsoft for alot of different reasons, so your problem may not be the same as mine. One sure way to tell is to count the number of email messages in your webmail inbox when you log into your yahoo account online. See if that number matches the the number that's displayed next to the "inbox" word. If the counts don't match, then you're having the same problem as I had."
Posted in case the linked content goes away.