Mac and windows servers can host files for clients of both Mac and Windows operating systems.
If you want to use FileMaker Server--not FileMaker PRo to host a database on a "regular computer", then you should go to the knowledge base (See link at top of this screen) and look up the system requirements for FileMaker server advanced to see if its OS version, RAM, CPU, etc meet the minimum system requirements for this software.
Thank you very much for the answer. Really appreciate your help. :D