How to download original videos from YouTube (lost backup copies from my computer)

[any ANONYMOUS forum user]

I've uploaded several .mpg files to my youtube accounts months ago. Originally I didn't keep backup copy of those .mpg files. Now I want to make backup copies of those videos in my computer.

I tried replay those videos via youtube. Then I got the corresponding files loaded from youtube to C:\Documents and Settings\<my xp login account name>\Local Settings\Temporary Internet Files with filename prefix get_video[1].* (PS: About 1-2 years ago I used this method to get playable copy of youtube videos). I played the file with VLC media player 0.8.5. Disappointedly, only the first few frames (less then 1 second) of the the video were played. Obviously, youtube had done something to disable this previous workable method.

I would like to know if there is any method to get back playable of my youtube videos? I'm using Windows XP Professional Version 2002 Service Pack 2 & IE 6.0