怪事，使用者皆可登入，唯獨管理員登入後會出現錯誤訊息而無法開啟頁面

突然間發生的
管理員帳號進不去了
會出現以下錯誤訊息：
Internal Server Error

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

Please contact the server administrator, webmaster@chader-union.com 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.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.
但是其他使用者皆可以正常登入使用
原本以為是瀏覽器的狀況
但後來發現不是
檢查檔案的時候發現.htaccess被更改了
於是將drupal原本的.htaccess檔上傳
不過仍然無解～
有誰遇過這種情形嗎？
請幫忙指點～～