Im guessing your cameras like mine an likes to use QuickTime but if not try Windows Media Player instead.

try right-clicking on a video you took,, an then select 'Open with' from the drop-down menu; then select 'QuickTime' an then select the 'Always use the selected program to open this kind of file' check-box.

if you have Windows 7 the steps are the same except for one tiny difference. you wanna choose 'Default Program' an then check the 'Always use the selected program to open this kind of file' check-box thingy.

that is of course also assuming you have a Windows OS. if not all the above us useless LOL