As USAF said, you cannot use a drive from an old laptop to be the boot drive on the new system - the old Windows OS is fully customized already for the hardware the laptop had. You will HAVE TO completely Install a new Windows on the boot drive of the new tower. Then you also will have to Install all fresh application software. THEN you can copy to that (or elsewhere) user-generated files from other drives.
Now, if you do want to use that one drive as your boot device, you can do that, but the process will completely wipe the drive and all your old files will be lost. So DO what you have done before. COPY all of the files from that drive to another. Later you can use that copy to re-copy those to their final destinations. For this purpose, instead of a slow copy-and-paste process, you might consider making a CLONE of that drive to another unit that has NO data you want to keep. After you finish copying old files from the clone to their final spots, you can wipe that clone unit and re-use it as an empty data drive.
Just a NOTE on this. When you go to Install Windows on the boot drive, it is best to have NO other drive unit in the machine. This trick is to avoid a "feature" of Windows Install that has caused problems for people down the road. Doing it this way forces Windows to place its hidden backup copies of critical files on the same drive unit so they can always be found IF that drive is working. (The default Install process is to place those backups on a second drive if present, but then that second drive ALSO MUST be in your machine to allow it to work.)
Here's an optional step. Once you have the old laptop boot drive cloned or copied and are ready to do the Install, consider this. The Install process will wipe out any record of its old data and "clean" all its old junk so it can't be found or cause any problem. But it will not actually wipe all the old data, and it will not test every part of the drive for errors to fix. Just to be cautious in re-using an old drive like that, I prefer to do a Zero Fill operation on that one drive before doing the Install. This operation writes zeros to EVERY Sector of the disk so all the old data is gone. But more importantly, that operation causes the HDD itself to do a test of every Sector as it works. Any faulty Sector will be detected and marked for "never use this one", and replaced from the HDD's stock of spare unused Sectors. When the process is done, not only will it have no data, but it also will appear to Windows to have NO faulty Sectors, like a perfectly new HDD. Now, that takes a long time to do the entire disk - hours! And it DESTROYS all data on that unit, so you must be VERY SURE when you do that, that is is being done ONLY on the particular old HDD you WANT to clean up!
For the second drive that is not to be used as the boot device but HAS files you want to keep, just wait until the tower has its boot drive all set up, then install that other drive (and any others) and you will "see" them with all their data available.