Thanks BugMeister for replying. Printer Make & Model No. Samsung ML-1640.
But I guess its nothing to do with the printer as stated earlier too, I have no issues in printing any document from any other Office application like Excel, Powerpoint, Outlook etc.
Also, when I have unistalled Office 2007 & installed Office 2003; I am having no such printing issues.
Installation of novaPDF Lite 7 printer has corrupted the printer settings of Word 2007. That is why I am also not able to open the Print Dialog box for changing the printer in Word.
Also, have uninstalled & re-installed the laser printer & set it to default but still no luck.