Hi,
My client's website has around 50 web pages. All the web pages have been indexed by Google. In most of the web pages, when I type the url of the page on Google, the indexed url of the web page gets displayed as a search result. For an example,

when I type - http://www.abc.com/xyz.htm , the search result comes up as www.abc.com/xyz.htm
Similarly, when I type- www.abc.com/xyz.htm, the search result comes up as www.abc.com/xyz.htm

This is perfectly fine. But for some other web pages, the search result varies.

Like, when I type- http://www.abc.com/pqr.htm, the search result comes up as "No result found"
But, when I type - www.abc.com/pqr.htm, the search result comes up as www.abc.com/pqr.htm

Taking all these things into account, I have some queries as follows:

1. Why there is discrepancy between http and www?
2. If it is there, how to fix it?
3. Any brief idea about http and www and how they influence the SEO?
4. It is possible that a site without having www, like http://mnc.com, will be picked up by Google

Hope, although it (queries) looks very silly, I will be grateful if I get a positive response.

Thanks in advance,
Rick