打开Control PanelAll Control Panel ItemsPrograms and Features
点击Turn Windows features on or off，显示.NET Framework 3.5 (includes .Net 2.0 and 3.0)未安装；可以选择打勾点OK后联网安装，也可以使用以下方式离线安装
下载Windows 10/11镜像，可通过刻录好的系统重装盘（U盘/光盘）或直接镜像解压路径安装.NET Framework 3.5 (includes .Net 2.0 and 3.0)，文件目录为Windows 10/11镜像下的sourcessxs目录，此处以D分区为例，如果目标处在其他分区，把D改为对应分区即可
以管理员身份打开Command Prompt或者Windows PowerShell然后输入以下命令
dism.exe /online /enable-feature /featurename:netfx3 /Source:D:sourcessxs
等待命令执行完成即可
然后再次打开Control PanelAll Control Panel ItemsPrograms and Features
点击Turn Windows features on or off，显示.NET Framework 3.5 (includes .Net 2.0 and 3.0)已经安装完成了
Windows 11 21H2正式版镜像下载
Windows 11 21H2正式版镜像_davidyezhiwei的博客-CSDN博客https://blog.csdn.net/davidyezhiwei/article/details/120630647
Windows 10 21H2正式版镜像下载
Windows 10 21H2正式版镜像_davidyezhiwei的博客-CSDN博客https://blog.csdn.net/davidyezhiwei/article/details/121406533
