Wax is pretty good and probably the best free program of its type. In fact, it's the only free program of its type I know of - a sort of free version of After Effects. It's not the easiest program in the world to learn though.
There's a few free editors around....
Take a look at the tutorials for Windows Movie Maker at http://www.windowsmoviemakers.net/Tutorials/ - it may be WMM is all you need. It really is foolproof except that it's picky in what file formats it takes and the lack of native support for multiple video and audio tracks are a definite disadvantage (but there are workarounds)
The version 2 series were probably the most versatile, you can find them here - http://www.brothersoft.com/downloads/windows-movie-maker.html - but you'll have problems installing the older versions on Windows 7.
Other free video editors are...
Wax - http://www.debugmode.com/wax/ - this is also a compositor - a bit like Adobe's After Effects - - unlimited video and audio tracks
VideoLAN Movie Creator - http://videolan.org/vlmc/ - up to 64 audio and video tracks
TrakAxPC - www.trakax.com/software/pc/
VideoSpin - http://videospin.com/ - just 1 video track so you may as well use WMM
VideoPad - the free version - http://www.nchsoftware.com/videopad/
Lightworks - http://www.lightworksbeta.com/ - I like this one - unlimited tracks ?
Serif MoviePlus - http://serif.com/free-video-editing-software/ - unlimited tracks ?
Ezvid - http://ezvid.com/ - 32 video and audio tracks
VirtualDub, RAD Video tools, AVITricks and Avidemux are also good tools you should look at. Although not full editors like the others they have some useful features.
Lightworks and Wax together are a very good video editing system for free.
All are safe, at least from the sites I've linked to.