It appears that HotBar, a graphical “skin” for Internet Explorer, causes the text editor in WordPress (officially, the TinyMCE editor) to behave erratically. If you’re not sure if you have HotBar or not, take a look at your browser’s toolbar–if it looks something like this, you’ve got HotBar.
The main problem occurs when a user with HotBar attempts to write or edit a post/page: Simply clicking in this content area will produce extraneous HTML table code. The coding may be removed manually using code view, but the real solution is to uninstall HotBar (which is considered to be Adware). A typical uninstallation of this program will resolve the issue, but please see this Web site for more thorough removal instructions from Symantec.