This behavior may occur if the temporary folder of Windows Update has been corrupted. We can refer t
win 7 64位系统上安装.NET Framework 4报：尚未安装 .NET Framework
解决：1、以管理员方式运行cmd2、在cmd命令行里输入：net stop WuAuServ3、在运行输入%windir%（如果这一步不能显示，直接按step4的路径找）4、在弹出的文件夹（如C:\w