Hi and welcome to Myce
IÂ´m sure we can solve this, but first we need to know a few more details about your system...
What kind of computer are you using, how old is it, what operating system is it using???
Can you watch any movies at all?
I will assume you have a Windows system: Where is the video file that you uploaded from the camera? What type of file is it? ...and what happens when you right-click this file?
When you right-click it, normally you should see a menu. Can you find "open with..." ? If so, click this and try to find "Windows Media Player". Does this work?
If we can get this far, we should be able to help you with the rest. Let us know.