5 sentences need help with

Could you help me with this please?

1 I'm boiling under this blanket/in this blanket.

2 I can't even do anything/everything I want in my own house.

3 Since you're no longer buying my computer off me, Instead of (you) owing me money, I owe you money.

4 Turn off the computer an hour before you go to bed so as to let your brain rest before you do.

5 3 days before I was due to get out of prison, I got a murderer as a cellmate. Those 3 days were horrifying.

6 In Who Wnts to be a Millionaire, it gets interesting and intense as of the second milestone.

Thanks