On a Windows system using IIS:
- Right-click on sites\default\settings.php and grant Write permissions to IUSR_MachineName (IIS6) or IUSR (IIS7).
Server 2008: You can also do this from the command line from within your sites\default directory:
icacls settings.php /grant IUSR:W
The installer will change the file back to Read Only after installation, but you should verify this after installation.
For more information about modifying Windows file permissions, see the Troubleshooting FAQ.
Drupal's API contains a pretty good description (Drupal 6, Drupal 7) of how node access works. Developers should also analyze the node_access function (Drupal 6, Drupal 7) itself. There are many contributed node access control modules for Drupal and you really should understand the basics of node access before installing and configuring one. The API should suffice for developers but for the benefit of our many community members who build sites without reading code, here is a translation and some basic rules of thumb (these rules were originally written for Drupal 6 - they have only been partially updated for Drupal 7):Read more