Magento - Is it safe to re-upload core data?

I'm having issues with my Magento store and I'm feeling like I may need to re-install the website. The first thing I'd like to attempt is simply re-installing the core data that comes from the installation zip file. The files are exactly as they were when I first uploaded them to install (in other words, config files are configured properly). Is this safe to do or have these core files been modified by the installation in such a way that re-uploading and replacing the current core files will br开发者_StackOverfloweak it?

Keep in mind that some developers do modify the core files (inappropriately). Not sure if anyone other than yourself has made changes, but it would be smart to do a diff on the core files against a clean copy to see what differences there are.

If you are re-installing the same version of Magento, then no problem. You can re-upload the core data files until and unless there is no changes done in core files before.

If the Magento version if different then you shouldn't.