asp.net4.0下载地址：https://download.microsoft.com/download/9/5/A/95A9616B-7A37-4AF6-BC36-D6EA96C8DAAE/dotNetFx40_Full_x86_x64.exe
asp.net4.0注册：
打开程序-运行-cmd:输入一下命令重新注册IIS
C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i
asp.net2.0注册：
C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\aspnet_regiis.exe -i