Want stay signed in even if I check the block for my e- mail

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Mike,

There is option where it ask remember your password, you need to click yes in that as well.
Hope this will work for you !

you email might be blocked by virus, register another one.

It is not caused by a virus, trojan, or anything like that! Yahoo have been making changes to the appearance of their home page and also their e-mail. As a result, the screen resolution of 800 x 600 on many PCs will no-longer allow you to sign in. Try changing your screen resolution to 1024 x 768

Many times the reason you cannot stay logged into your mail account is because of cookies. Gmail will try to set a cookie in your internet browser. If you are blocking cookies or otherwise not accepting cookies, this may contribute to the problem you are facing.

It's true with respect to "active state" of mail, so if you put idle for some time you may need to login even when browser is still open. so, try to be in touch of messanger

I was having the same problem with gmail, and the porblem is your outgoing settings are off. I don't know what yahoo is, but I know google change to a higher port.

Try going back to Yahoo classic mail. Many of us had problems using the new mail and the spell check doesn't work. With the classic, I stay signed in for 2 weeks, the spell check works, and it works with the psp. I think they can keep the new mail. It sucks.

One option would be to get a Gmail account at Gmail.com, as it is great at blocking spam, and any that gets through, you just have to mark as Spam and you won't see it again.
If you have to stay with yahoo, there are many third party spam blocking softwares available to help you out. Yahoo may even provide Spam blocking feature (I don't use yahoo, so don't know for sure).
Good luck