how to identify your .NET Framework version

scenario:

when I try to install github-windows on my PC, got such error "lower .NET Framework Version" :

Prerequisite check for system component Microsoft .NET Framework 4.5 (x86 and x64) failed with the following error message:
"Installation of the Microsoft .NET Framework 4.5 is not supported on this operating system. Contact your application vendor."

how to identify your .NET Framework version:

regedit->HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5

refer to 如何确定已安装的 Microsoft .NET Framework 版本和 Service Pack 级别

or just check "Add or Remove Programe" Panel,

download .net Framework 4.5

before download v4.5, you'd better check you environments:

Supported Operating System
Windows 7 Service Pack 1, Windows Server 2008 R2 SP1, Windows Server 2008 Service Pack 2, Windows Vista Service Pack 2
Windows Vista SP2 (x86 and x64)
Windows 7 SP1 (x86 and x64)
Windows Server 2008 R2 SP1 (x64)
Windows Server 2008 SP2 (x86 and x64)
Hardware Requirements:
1 GHz or faster processor
512 MB of RAM
850 MB of available hard disk space (x86)
2 GB hard drive (x64)

maybe it's why github-windows just support Windows Vista, 7, 8, & 8.1 ,check it https://github.com/

official download .net framework v4.5