I want to use Microsoft office webapps server 2013(OWA) with my sharepoint 2013.Although I am maintaing my sharepoint 2013 server on another machine since that is the requirement for the installation of OWA but still error is coming. The following error keeps popping up.I have windows server 2012R2 installed.
As the error message says, you have some reference to SharePoint on the server, even if you have removed SharePoint from it. My suggestion is to reinstall Windows Server 2012 R2 from scratch making sure you don't have any reference to SharePoint at all. It's a bit of work, bur it usually pays off to make things right from the start.
I once tried to install SharePoint 2007 on a server which had SharePoint 2010 on it. I uninstalled SharePoint 2010, used Microsoft Fix-It and ended up hacking the registry - all without any luck and two days to waste. Reinstalling solved the issue then.