1.     Open "Programs and Features" in Control Panel (also known as  Add-Remove Programs):

2.     Uninstall all instances of Visual Studio 2010 products (for example, Visual Studio 2010 Ultimate).

3.     Optionally, uninstall the following supporting products that may have been installed with Visual Studio 2010.  NOTE: These components may also be used by other product suites on your computer.

    a.    Web Deployment Tool

    b.    Silverlight 3 SDK

Silverlight 4 SDK

Silverlight 4 Tools for Visual Studio 2010 RC

    c.    Visual Studio 2010 Tools for SQL Server Compact 3.5 SP2

    d.    SQL Server Compact 3.5 SP2

    e.    SQL Server 2008

Reboot needed.

    f.    SQL Server 2008 Native Client

    g.    SQL Server 2008 R2 Management Objects

    h.    SQL Server System CLR Types

And other SQL Server series..

Blend series, include SDK, IDE.

4.     Uninstall other remaining supporting products, in the specified order.  (Ignore items that are not present on your computer.)

    a.    The .NET Framework version 4 Language Pack

    b.    The .NET Framework version 4 Extended (reboot, if prompted)  

You can skip reboot and uninstall item c (see below) first.

    c.    The .NET Framework version 4 Client (reboot, if prompted)