I have registerd my own domain name and web hosting space too on parallels
thay are having there plesk control panel.
I know that for html pages I need to copy my all pages into httpdoc folder
But what about by MVC WEBSITE?
HOW DO I HOST IT?
CAN ANYONE HELP ME?

you have to copy the whole mvc project into httpdocs folder to view it online.
You are getting the 500 – internal server error may be because the
mvc versiondiffers in the server(i mean may be you are using mvc v4 and the server has mvc v2).So just contact your hosting provider, i am sure you will get a good solution.