Your blockland folder might be partly read-only?
I have this problem, and I'm experiencing exactly same things as you.
I don't have this problem, and half of my Blockland folder is read-only. I
like my custom guis thankyouverymuch.
Your computer is probably reinstalling the wifi antenna every time you restart it. Maybe there's some way you could remove the hardware so that it doesn't... do that?
Or. Maybe you could keep your key in a text file somewhere and use a command like setKey("BLAHBLAH"); to put it in the console quickly right after the game loads. (Ctrl+V won't work outside of the ingame console. I think if you click on the logo in the upper left corner, then edit, you can paste it from there)
Or. You could get a desktop PC.
Other than that I don't really have any suggestions. So... no solution to your problem. Just workarounds.