tedster - 12:11 pm on Oct 12, 2010 (gmt 0)
Hello birendra, and welcome to the forums.
I haven't seen any effect like this, and I'm glad you reported it - it is very unusual. In most cases an "orphan" page that has no links from other pages on the site will have a lot of trouble ranking at all.
Do these pages of yours have strong backlinks from other websites?