Installing Visual Studio Versions Side-by-Side
Visual Studio 2010 can be installed on a computer that already has an earlier version of Visual Studio.
We recommend that you install Visual Studio versions in the order in which they were released. For example, install Visual Studio 2008 before you install Visual Studio 2010.
Before you install versions side by side, review the following conditions:
If you open in Visual Studio 2010 a solution from an earlier version and then save the solution, you can no longer open the solution in the earlier version.
If you uninstall a version of Visual Studio on a computer that has more than one version installed, the file associations for Visual Studio will be removed for all versions. You can remap these file associations by using the Restore File Associations button on the Environment, General page of the Options dialog box.
Visual Basic and Visual C# projects use the Target Frameworks property. Visual C++ lets you manually specify runtime support. For more information, click a topic in the following table.