Go into windows movie maker, is on most computers from the factory. Import the video you want. Put it on the time line. (Drag and drop)
Go to File
Save for email (even tho your not emailing it)
When it's saved...put it in "My videos"
Then you can upload it to photobucket, or you tube from "My Videos".
I've started using You Tube because photobucket videos never will play for me when I try to watch them.