.htaccess使浏览器打不开解决思路

.htaccess使浏览器打不开
一页面很正常，可是当我在根目录下放入.htaccess，该页面再也打不开了，
.htaccess的内容:
# Helicon ISAPI_Rewrite configuration file# Version 3.1.0.66
RewriteEngine On
RewriteRule ^index.html$ index.php
RewriteRule ^index_ok.html$ index_ok.php：
页面显示：


Internal Server Error


The server encountered an internal error or misconfiguration and was unableto complete your request.
Please contact the server administrator, gg@tom.com and inform them of thetime the error occurred, and anything you might have done that may have causedthe error.
More information about this error may be available in the server errorlog.

------解决方案--------------------
#有没有加这个？
RewriteEngine On
RewriteBase /
RewriteRule ^index.html$ index.php
RewriteRule ^index_ok.html$ index_ok.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d