Windows Movie Maker.
http://download.cnet....er=platform%3DWindows
I recommend this mainly because it's very easy to use. Easy to add effects and edit video.
For the things your looking to do, this would be my best/most suitable suggestion.
Copy & Paste the URL - will give you choice of downloading Windows Movie Maker for XP + Vista.
If you have problems with the URL........
www.download.com
[i]at top of page you will get a search box[/i] *in that type windows movie maker*
Select either XP/VISTA and
1 - Read the reviews from others who've downloaded
2 - ALL downloads are free & NO software is a threat to your computer in anyway.
(Should you have any questions or require further help, then please just ask.)