The HD is OK to re-use the OS however is not. You can't re-use the OS from an OEM type system like HP or Dell, etc.. The OS is tied to the original PC. If on the other hand, you have a retail version of the OS, then you can re-install it, but not the current one on the HD as that more than likely won't work anyways due to h/w issues when it was 1st installed. Go ahead and try and learn.
I imagine that this has been asked many times before, but for some reason I can not find it, the threads I can find seem to be dated...
Can I take the old HD out of my computer and use it as the Master in my new build? My computer is fairly new, but I am attempting to build a computer with a better processor and some bells a whistles mine currently does not have. I would like to use the old HD because there is nothing wrong with the HD itself or the OS, I am looking to save a little money on having to buy a new copy of my OS, if possible.
I also plan on adding another HD, but had plans on using that as a Slave, if that makes a difference.