Where are the Visual Studio settings stored?

Make an Export of your Visual Studio Settings... Tools -> Import And Export Settings Afterwards you can import it to your VS where you want have this settings.

**Update for latest version**

Visual Studio 2015:

%USERPROFILE%\Documents\Visual Studio 2015

Visual Studio 2017:

%USERPROFILE%\Documents\Visual Studio 2017

Also have a look at these folders:

%USERPROFILE%\AppData\Local\Microsoft\VisualStudio\...
%USERPROFILE%\AppData\Roaming\Microsoft\VisualStudio\...

Try copying the files over from the old profile in the following locations to your new username's profile:

From:
    C:\Users\[OldUSERNAME]\AppData\Roaming\Microsoft\VisualStudio
To:    
    C:\Users\[NewUSERNAME]\AppData\Roaming\Microsoft\VisualStudio

From:
    C:\Users\[OldUSERNAME]\AppData\Local\Microsoft\VisualStudio
To:
    C:\Users\[NewUSERNAME]\AppData\Local\Microsoft\VisualStudio