After D8-rc1 install, homepage work but all other links gives a "page not found" I upgraded my Xampp to version Xampp 5.6.12 since Drupal 8 need PHP to be 5.5.9 or better.
I checked out a couple of my Drupal 7 website under the htdocs dir.  They are working fine.

I installed clean drupal 8 in the same htdoc dir under "newd8" folder. I used instructions so that I don't do make any mistakes.

The installation is fine and the default homepage came up at "http://localhost/newd8" and admin login account is working.

BUT clicking on any of the admin menu items, I get "page not found" drupal error. for example, if I click on "people", it goes to the link "localhost/newd8/admin/people" but I get a "page not found"  page.

If I modify the URL to include index.php, thus "localhost/newd8/index.php/admin/people", it works.  I get the right page.

This seem to be for all the pages.  if I manually add "index.php" at the appropriate place, I get the required page.

I have modified the base URL in the  setting.php file then its css file is not loaded properly even home page layout is totally disturbed 

What am I missing?
I fixed this.. Thanks to Sumit, I read the .htaccess file more carefully.. Inside the default .htaccess file that comes with the Drupal 8 download, around line 108, comments tells what to do if d8 is installed in a sub-directory instead of document root. I modified line to "RewriteBase /newD8" and now the site works. Even though the same comment is in the D7 version too, On the same Apache server and same document root, D7 works without the modification of the line but D8 needs the change. I don't know why. Because of Symfony perhaps?