I'm in no way a computer expert so take the following for what it's worth.
If someone is attempting to hack into your email account you more than likely won't know as your account sets on a server somewhere unless you're still using the old style system where you actually download your mail to your computer. Also if you're getting a popup asking for info certainly don't give any out and note what page your accessing on the internet and what you just clicked on.
There is a Windows Live Team Phishing Scam going around...go to the links below to view other people who have been hit. It may lead to more info.
WARNING: Windows Live Team Phishing Scam
Windows Live Team Alert Confirmation - Microsoft Answers
I use gmail and this is what they do if they detect a problem on their server and this just happened to me a month ago. According to gmail someone in South America tried to access my account. Gmail then locks down your account and ask for a code at the log in page which you don't have. You follow the yellow brick road and your led to a page where your given a code and a phone number and instructions. You call the number and enter the code then they send a return code via text which you enter back on the original log-on page. Once your back in your forced to create a new password then wala your back in. Pain in the rear but necessary I guess.
One needs to change the passwords on all your accounts on a regular bases. Hackers don't break in they figure out your password and they don't necessarily want to look at your mail they just want to use the system and remain unknown. Also you need in place a good firewall and antivirus on your computer.
Hope this helps somewhat.