The only way I could get to work in my Windows 8.1Windows 8.1 is the following: Add
Add to system environment variables (not user variables):
cC:\Users\USERNAME\AppData\Local\GitHub\PortableGit_YOURVERSION\bin;c\Users\USERNAME\AppData\Local\GitHub\PortableGit_YOURVERSION\bin;C:\Users\USERNAME\AppData\Local\GitHub\PortableGit_YOURVERSION\libexec\git-core;ccore;C:\Users\USERNAME\AppData\Local\GitHub\PortableGit_YOURVERSION\cmd\
This fixed the "it looks like gitGit is not installed on your system" error on my Visual Studio Code.