Pixelation in Quicktime Videos - HELP!

[southphillygirl]

I know only the bare minimum when it comes to my Mac, and definitely do not understand technical jargon!

My problem is movies I uploaded to my Movies Folder in Finder from my own digital camera - videos of my kids - have suddenly started pixelating when I open them using QuickTime. They've been fine for 2 years, now suddenly all distorted. i did all the things a technical dope like me could think of - restarted the Mac, did a software update, downloaded QuickTime 7.5, then restarted - and nothing is making the pixelation go away.

Does anyone know what the problem is? Is it in QuickTime or is something wrong with my Mac? Are my movies corrupted somehow? Is there a solution?

And please, talk to me like I'm a 4-year-old since I won't know any technical terms. Thank you!!

[dr dave]

My first step when it acts goofy is to repair permissions. BTW, you will want to tell us about your machine, OS, and so on. Knowing the camcorder model may help, too. I don't understand how you uploaded your videos. iMovie? Final Cut?