Hotmail comes in through your browser. In your case IE. It is called a favorite if you save it on your desktop. You can't open a browser favorite (hotmail) without having it open in a browser.
Under Win7 you cannot pin a favorite to the taskbar, you can only pin it to your browser icon on your taskbar.
If you want to get to a hotmail account without going on the internet, you will need to install a program such as Thunderbird which will read your emails and put them on your computer for later reading without the internet.