Of course you can reuse an old drive.
Now would need more specifics on if the drive is a secondary/third drive or if it is your OS drive.
If it is your OS drive then you cant take an existing build of windows and just put it in a different PC. Not only is there a windows licensing issue with that, but that install of windows was done on the hardware of the old system and will at best be unstable at worst not even boot when you put into a completely different PC.