If you need to put together a new video or slideshow, I'd highly recommend checking out the Audio section of the iStockphoto website.
They have thousands of royalty-free audio tracks that are truly fully cleared. Buy the track and you can use it for just about anything with no additional rights to by or legal worries.
A lot of folks think they can use ANY track for "personal" use.
Nope. You cannot post to the web, show as your portfolio, use less than 30 seconds, etc. BE LEGAL and buy your music.