HTTP 500 error with WordPress

HTTP 500 error is a very common internal server error, there are many such errors, here only in WordPress inside the more common HTTP 500 error.
We use the WordPress plug-in when they will encounter such a problem, because the plug-in version and we use WordPress conflict, solve this problem as long as the plug-in can be disabled.
We will be in the upgrade WordPress time will encounter such a situation, when you put the new version of WordPress program files uploaded to the server to overwrite the original old WordPress program files (or you will be the old version of WordPress database into the new version of WordPress database) You will visit the site will appear HTTP 500 error, the website can not visit how to do? There are two main cases of such errors:
1. The PHP program in your topic is not compatible with the new version of the WordPress program. To resolve this error, you first need to use the FTP tool to rename the topic you are using on your site before attempting to visit the site.
2. is due to a plug-in and the new version of the WordPress program is not compatible, to solve this error as long as the FTP tool to delete all the plugins on the site, and then log on the site to try to install a plug-in, find the problem plug-in.