Google Auth on Windows

We strongly advise you to use one of the options on a mobile device, using the same desktop for GA as your using to login defeats much of the point of using MFA.  This allows comprimising 1 device to comprimise both credentials. 

However if you dont have a mobile device there are several options that will work.

There are Browser plugins for Chrome and Firefox that will generate GA codes. Here is 1 example

Authy is availible for Windows.

WinOTP will also generate codes.