Very simple video editor

You need Windows Movie Maker, it's free, made by Microsoft for Windows, is made to serve "dummies" and does everything you need.

If you have Windows XP, it should already be installed in your computer, look for it in: Start > Programs > Accessories.

If wou've got Windows 7 or Windows Vista, it comes with the Windows Live suite. You can download it here.

Windows Movie Maker:

Sony Vegas will surely fits your needs: I found it very funny and intuitive (being a total noob at video editing!)