Not using styles is really a mistake, but to do what you want first, with no text selected make sure that the character style is set to [None] so you don't have a character style applied by default (it's possible this is set for all docs accidentally, so you may need to redo this with no files open).
As far as I know you cannot set a no style default for a paragraph style in CS4, or at least not easily (might be doable by script), and of course whatever formatting you've got set is going to be used, regardless of the paragraph style selected. You can however, create a new text frame and use the flyout menu in the Paragraph Styles panel to "Break link to style" and that rame will have no paragraph styles applied unless you go back and apply them later yourself. Your screen shot shows a table, though, and I'm not sure it's possible to have no paragraph style in a cell.
Thanks a lot for your valuable feedback.
I do not want to use "Break link to Style" for content occurs in text frames. When we do that it removes both paragraph or character styles that was applied in that text frames. I just wanted to do only table that is occurs in text frames. Is that working well any issue?
As I said, I don't know that it's possible to not use a style in a table cell, and I'll repeat that you almost certainly SHOULD be using styles. They make life much easier. You can define cell styles based on paragraph styles.