500 Internal Server Error after Windows reinstall

I work at a site (in WordPress 3.2.1) for some time, as Windows (Win 7) was about to crack from one point to another, I decided to reinstall it (Win XP this time). So I saved all your “www” and “bin” of Wampp Server on a DVD, and now after I finished reinstalling Windows and Wampp Server , I did replace the folders (www and bin) fro, C: / wampp, with those saved on DVD. The problem is that the site no longer load . Localhost url can not be accessed but phpMyAdmin page is okay.

When I try to load https://localhost , error:
Page name – 500 Internal Server Error

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, admin@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Which is the problem?

I mention that the sites are in wordpress and wampp server was not used when I’ve replace folders. I have this problem with athor 4 site as well.

I’ve tried also to put the file online and work with it from there, but same problem. Maybe I’ve made some misstakes, but where. Can you tell me the right process to move a wordpress site from localhost (using Wampp Server) to an online server?

Thank you in advance!