I can help you,
I've been making movies for YouTube for a good 4 years now.
Use Windows Movie Maker 
2.6 that's pretty basic.
Although, It crashes alot and it isn't the best but it's free.
If you don't want to use that, I suggest downloading Windows 
Live Movie Maker.
This is a 'cleaner' and 'stripped down' version of the original as it looks better and you can actually save movies in High Definition which is brilliant however:
Effects, Audio Editing, Loading, Transitions etc
Are all a problem in the latest version.
Both of those versions don't work for me anymore, and I'm not the only one.
I find alot of people give them bad reviews because they basically suck but are easy to use at first, until they begin crashing.
If you don't want to use those two, I suggest jumping to the one I now use.
It's called 
ImToo Movie Maker 6.
It's very useful and clean and it just seems better, I haven't tried saving on it yet so I don't know what a finish product looks like on it yet but you know, It's not bad from what I've seen.
The only 2 Problems are that you can't control where you place Audio, which is a great shame.
And the effects are very dull and boring.
Those are the 3 I recommend if it's your first time, there's always Sony Vegas but that's more for Professionals, like Film Editors. 
I'll give you the download links for the 3 I Mentioned:
Windows Movie Maker should already be on your computer
Windows Live Movie Maker
Download ImToo Movie Maker 6
I just noticed from giving you that, that Windows Live Movie Maker has a new version out.
The one I have is 2009 and they appear to have a 2011 version out, I wonder if it's going to be any better, Might give it a go myself.
But yeah, Good Luck 
