Can I?

Is it possible to get windows onto another computer by copying the windows folders onto a different hard drive. I have a laptop with windows but did not get the license for windows? I am looking to build a low end sarter pc and I want to save the 80-100 dollars on windows if I can.

It's not a technical issue (though straight up copying won't work), it's a licensing one. I'd assume the laptop game with a Windows license, but if you read the EULA, you'd find it's only for that specific laptop. So, you'd technically be pirating Windows if you put it onto a second machine without a license.

If you need a new PC, may I recommend Linux Mint as on OS? The Cinnamon version looks quite nice indeed, and runs a respectable number of games.

Nope.