How to get rid of the little bastards?
My method is below but a commenter below suggested using Ctrl+Q which you might like to try first:
Highlight the area of concern and click on the Page Layout tab in the menu (File | Home | Insert | Page Layout). Swear for a bit until you spot the word 'page borders' in the 'Page background' section of the ribbon thing. Click on that and then click on the Borders tab on the left (you'll probably be on the default tab in the middle which is Page Border). Click the 'None' setting in the left and then OK. This should magically remove the lines. [See pictures below]
If you get into real difficulty the only foolproof way I've found of wresting back control from recalcitrant text is to copy and paste it into Notepad (try C:\Windows\system32\notepad.exe but if not it's Start > notepad [then press enter]) which strips the text of all formatting allowing you to start from scratch.
I use Notepad more than I use any other software programme, before transferring text to whatever programme I want to save it in. If it's really important stuff I tend to write it directly into Evernote and I press Ctrl+S very frequently to make sure I've saved it. Word has its own autosave which is useful but I nearly always start a document in Notepad.
Picture 1 is what happens when you create a solid line using the hyphens... you can use the option that appears just after you create one to nip future solid lines in the bud but for previously created lines see picture 2.
Other posts in the Word tips series...