Setup General Information
The July 2002 Library is designed to be compatible as the fully integrated Help system for Visual Studio .NET. The July 2002 Library, and all future Libraries, will not integrate within Visual Studio 6.0 or earlier versions. If you are running Visual Studio 6.0 or earlier, the July 2002 Library may be used as a standalone product.
You are not required to uninstall previous versions of the MSDN Library that use Microsoft Help 1.x technology. For example, the October 2001 MSDN Library and all earlier libraries will coexist with the July 2002 MSDN Library. If you wish to uninstall any Library, always use the Add/Remove Programs option from Control Panel or the Setup program from the CD of the MSDN Library you want to uninstall.
死心吧!不行就是不行,安装说明的很清楚!