Quicktime problems--"bad public movie atom" message
I love to watch film trailers, and Quicktime is the program I normally use. I recently got a new Dell PC and every time I click on a Quicktime link I either get a "broken" image of the Quicktime logo, or I get a message saying something to the effect of "this file could not be played because it contained a bad public movie atom."
I have no idea how to fix this problem, and I am a relative novice when it comes to computer language. So please be gentle!
Thanks in advance to anyone who can help me out.