I would be more concerned about using Windows if I were you. Sure, removing everything that's going to connect your computer to any network is critical, but it's even more concerning to use closed-source OS that is known to having the most vulnerabilities: https://www.beyondtrust.com/blog/entry/microsoft-vulnerabilities-report

Installing a Live OS like Tails would be preferable.

You should obviously only install peer-reviewed, tested wallet software, and verify their binaries.