Well, I have never done or tried such on a pc though, but I've done something similar on a mobile phone, like' I bought a small android device for this purpose alone, I turned it on, installed a sim and connected to the internet, downloaded mycelium bitcoin wallet, moved most of my bitcoin in there, and after the transaction was confirmed and I was sure of it, I went into my settings, located the network setting and deleted the internet configuration, and immediately, I was disconnected from the internet even with sim card installed and data connection turned on, I then turned the phone off, remove the battery as well as the Sim card, and kept the phone some safe.

I assumed it to be a hardware wallet or a cold bitcoin storage, i left it like that for over eight( months before I decide to turn the phone back on, Installed the Sim and requested a new internet configuration from my service provider which was sent immediately, I install it and was able to connect to the internet again, open mycelium wallet and my bitcoins were sitting right there waiting for me.