Welcome to our Community and thanks so much for joining our forums - sorry to understand that you're having some issues with the TVGo app on some of your devices.
When accessing TVGo via an browser, you do need to use the same browser each time - if you use a different browser or via a new window, this will count as a new device. It will also not work correctly if you have pop up blockers enabled.
When using the app on Windows 10 - you should not need to download the app each time; you just download the app once and then log in on the app each time.
Please also be advised that you can only log in using the Primary log in details for your MyVirginMedia.
For more help with the TVGo, you can check this link