This is one of the new-bie questions normally asked by folks who are new to Microsoft word 2007. A lot of new changes have come in, including the format in which the file is saved. Getting back to the problem, the following might be a solution you are looking for :
1> Click in an affected paragraph.
2> Click the Home tab on the Ribbon.
3> Click the arrow in the lower right corner of the Styles section.
4> The style for your paragraph should have a bold box around it.
5> Hover the cursor over the style. A list box arrow should appear. Click it.
6> Select Modify from the list box.
7> Click the Format button and select Border.
8> Under Setting, click the None box.
9> Click OK.
10> If you want this to carry forward to other documents based on the template this one is based on, click the radio button for New Documents Based On This Template.
11> Select OK and you are good.
Once you’ve followed the above steps you should be good and all the paragraphs in the document with that particular style should auto arrange.
However, When you try to close your document, a security warning may pop up which might ask you if you want to save the changes done to the ‘Normal.dotx’ . This is a regular anti-virus alert intended to send a security alret that there has been some changes to the default .dotx. If you are sure that you have made changes to suit your requirement, then select OK and everything else will be just fine.