Need video help....

[Nick.V70]

I have been taking more video's on my camera and for some reason I am having a hard time watching them on my computer. The camera takes HD video and now when I down load them off the camera to my computer the video doesn't show a screen shoot only a white face that shows the Quick Time logo. I go to open and it takes FOR EVER to open and then its weird and freezes. Is there another software I can down load that you guys are liking to use? Before it was opening my old videos that where standard/not HD with Window Media I think.

Sorry I am lost when it comes to this stuff.

Any help would be great...

Thanks