Your harddrive just stores data, it has nothing to do with the rest of your hardware. What will happen is when you first boot up windows will find a bunch of new hardware and try to install drivers... so you better have internet access ready and/or the drivers that came with the new pc. Sometimes the license of windows will need to be re-activated, which, again, isn't a huge deal. Understand that, of course, you can't have the same license on two different pcs, so you will need the license that came with the new pc on hand.