Microsoft Word may be a relatively safe and familiar tool for you, but it is not very friendly when it comes to creating content for the web.  If you are editing or adding content to your site in Wordpress, Drupal, Joomla, or any other web-based wysiwyg editor:

Don't copy and paste from Microsoft Word!

Word creates a lot of ugly code that gets copied and pasted into these editors.  The results can be disastrous.

So what's the solution?  If you aren't willing to ditch Word, there are two simple options.  The first is to first paste the Word content into a simple text editor like Notepad (Windows) or TextEdit (Mac).  These programs will strip the Word-specific code out.  Copy from there and then paste into your editor.

The second option is only available in certain editors and can be called a number of things; "paste from text," "paste from word," "paste from document," etc.  In Wordpress you have to open up the "kitchen sink" of the editor by clicking on the icon you see to the right here.  Once opened, there are two icons for pasting from Word or other applications.  When you click on those, they open a small window where you paste your content.

While on the subject of Microsoft Word, why don't you just stop using it altogether?  It's expensive, glitchy and 100% replaceable.  Try OpenOffice.org or Google Docs instead.