安装时提示Web Applications unavailable，解决办法如下：
开启Windows的如下功能：
· Web Server (IIS)
· Web Server
· Common HTTP Features
· Static Content
· Application Development
· ASP.NET
· .NET Extensibility
· ISAPI Extensions
· ISAPI Filters
· Security
· Basic Authentication
· Windows Authentication
· Request Filtering
· Management Tools
· IIS Management Console
· IIS Management Scripts and Tools
· Management Service
· IIS 6 Management Compatibility
· IIS 6 Metabase Compatibility
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