I think if you do things with a little bit of knowledge and attention then there is no issue at all while using cryptocurrency. I know there are still lot of phishing attacks and keyloggers running all around but it's a truth that a little bit of attention while making transactions can save you from scam.
Using used computer parts is risky, even if you have enough knowledge and pay attention to securing the safety of your wallet, we really can't tell the if it is safe unless you know the seller, you can assure that he won't fool you when it comes to the parts of the computer. But of course, it's better to buy new parts even if it's cheap, just to secure your own safety.
But the thing is that why do such things? Always buy from genuine part seller and never ever buy second hand especially when you have to do crypto related things on your PC. Moreover never install any third party softwares from unknown sources on your computer and always use genuine windows I think these things are enough to save you from any scam.