why cant I use my normal email address to access all windows functions in win 8.1

Hi!

The short answer is that your normal e-mail address isn't a microsoft-address. (Which is needed for the single sign-on features)

The following link will give you more information: http://windows.microsoft.com/en-us/windows-8/microsoft-account-tutorial

Best regards
Andreas Molin

Hi,

We need to use Microsoft account to log on Windows 8.1.

A Microsoft account is an email address and password that you use to sign in to Windows. It's free and easy to set up, and you can do so with any email address you choose, or get a new email address. (For example, you can use an Outlook.com, Gmail, or Yahoo! address for your Microsoft account.)

If your personal email account is Gmail or Yahoo, you can log on Windows 8.1 as Microsoft account.