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?

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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.

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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.