Ok, it's still a 500 with all plugins deactivated?
We may be able to help, but we'll need a more detailed error message. Internal server errors are usually described in more detail in the server error log. If you have access to your server error log, generate the error again (load the page and see the 500), note the date and time, then immediately check your server error log for any errors that occurred during that time period. If you don’t have access to your server error log, ask your hosting provider to look for you.
