A question I had when I started learning about PoS that isn't addressed here is "how much interest can I earn per year". The answer is it depends on how many people stake, and the numbers aren't finalized yet, but estimates are that you should be able to earn 2-6%. We won't know for sure until it's live and being used.
I still have trouble getting my head around proof of stake. I feel like it's akin walking into a bank to get a loan, and when they ask you for collateral, you give them the contract for the last loan they approved, and its just a room full of people doing this over and over.
Isn't having something like collateral or work that is external to the system a key part of keeping value in check?
Any computer or laptop can stake. Your computer will need to be online 24/7 to stake.
You will need to download an Ethereum 2.0 wallet when it releases and start staking through the UI. 6 or so of these are being built and you can check it Prysmatic Labs to see the progress on theirs.
You will only make a few blocks a day depending on how much you stake. It's not too intensive from what I've seen. I think it will work fine even on a slow HDD.
One important thing to note is that the proof of stake Ethereum chain is a different chain than the proof of work Ethereum chain. You won't need the legacy PoW chain to stake.
With PoS you only need data from the last checkpoint to stake. This is only a subset of the entire chain. You also only need the data for the shards you are a validator for which further reduces the data required. The goal is to allow anyone to stake if they want to regardless of hardware in order to increase decentralization.