Can't get vimrc working on windows

It was very straight forward on my linux server. Create the file and add what I want and away I go.

But in windows Ive been messing around for a while and no progress.

Im also baffled as to what file extension I should save it as since there isn't one existing already in my user\name folder where the vim -version points to.

Ive tried both .txt and .bat to no avail. Also tried _vimrc and .vimrc.

I also tried saving lines to the vimrc in program files\vim\ folder but I'm not allowed to save it. Even on a fresh reboot when I try and save I get the popup saying the file is in use by another program.

Please vim lords what must I do?