Summary: Use Windows PowerShell to find the size of your user profile.

 How can I use Windows PowerShell to find the size of my user profile and to see the size of the largest file in my profile?

 Use the Get-ChildItem cmdlet, recurse through your profile directory, pipe the results to
          the Measure-Object cmdlet, select the Length property, and add Sum and Maximum.
          This command measures the ED directory, and dir is an alias for Get-ChildItem:

PS C:\Users> dir .\ed -Recurse | Measure-Object -Property length -Sum -Maximum