There are bitcoin mining methods with computer and home methods and you can do this, but your cpu and graphics card will be severely damaged during this operation.
It won't. Trust me, it's just terribly inefficient.
I think except for one or two well rounded response, none of them specifically answers the problem as to why switching to another algorithm will not work. Bitcoin's mining industry is huge and the ASICs being used is not cheap at all. Any attempts to change Bitcoin into a PoS will undoubtedly be met with opposition from all of the miners. Proof of work, as the name suggests entails that work is being done during the mining process. This means that effectively, mining is a way to give up certain resources in return for compensation in Bitcoins. In this case, the resources that is continuously being used up is the energy consumed by mining. This ensures that if any attackers were to attack Bitcoin, they need to have sufficient resources and thus potentially resulting in a largely negative ROI after the attack.
PoS is fundamentally flawed.