Can I watch Bluray movies on a Windows 10 laptop?

Can I watch Bluray movies on a Windows 10 laptop?

If your drive can read Blu-Rays: yes.

If you have a BlueRay drive… YES

And how do I know that

If there's a drive installed that "can" Blueray and a corresponding software player is installed, nothing should stand in the way…

Yes. If the computer has a Blu-Ray drive and software to play it.

If you have a BluRay drive in your laptop and the corresponding playback software, of course

By checking the specifications of your drive.

The easiest:

Put a Blu-Ray disc in the drive and see what happens.

That should be on it (not only the CompactDisc logo but also the Blu-ray logo).