If you’re installing from scratch, start again. It’s really not worth chasing around after.
If you’ve got a half-decent host you should have Fantastico in your control panel, which makes it literally a five minute instal.
If it’s anything to do with your.htaccess file, it probably ought to look like this and should be a level above the wp-admin folder.
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
