Check the event.log file in the FMS logs folder.
It could be as simple as you having FMP open at the time. That would prevent FMS from grabbing port 5003.
I did not have FileMaker open at the time of installation.
It goes without saying, but did you delete the FileMaker Server folder and reboot after deinstall?
I've done several with no issue but always do that.
Did you solve this Cindy - today I'm having exactly that issue so would love to know how you sorted it out...!
I started having all of my issues with the MacBook Pro after I installed a piece of Cisco software I was using to create a VPN connection. I have moved that to my Windows laptop and things are working now.
It was a very frustrating process.