Your current copy of Windows will be set up for your current motherboard, graphics card, etc, etc.
It certainly won't "just work" in a new system - at the very least it'll need to redetect all the new hardware and reset itself for it. Very possibly it won't be able to startup at all.
However if you install it as a secondary drive (slave to the drive in the new system, or in an external USB caddy), and your new drive has Windows already set up on it, then you'll be able to get at all your data on the old drive and copy it to the new one.
You need to tell us exactly what you want to do with the drive, and what you re getting in the new system, otherwise all anyone can make is guesses.