How do I get my computer to notify me when I get a email?

while I am on my computer I want to know when I receive a new email

I am personally disgusted at the fact that you can get onto anyone's email VIA YOUR COMPUTER'S HISTORY and learn possibly their most personal things. I've only accessed my own email accounts on Yahoo and Hotmail using my computer's history but there...

I have email account that I share with my sister for our rental cottage. Last week a friend was over and used my computer to check her email. Now when I go into Yahoo.com, her account/email comes up! How do I get rid of her email and get back to mine...

i want to know if theres any way i can get my computer to make a sound when i get an email on this email like on aol when it says youve got mail

my previous yahoo IM, would show a pop up of when i received a email but on my new IM it wont pop up to notify when i get a email no matter how much i change it in the preferences

Can I set my email so that when I get an incoming email my computer with make a sound to let me know I have new email.

I just email someone in yahoo answer in their profile so does will I get notify if the email is sent?

I get an error message saying the website is unavailable and/or experiencing difficulties and cannot find the server. However, when my sister checks her email and I do have another personal email account that I have been checking and have no problems...