I'm trying to access world science day which uses unity web player. However, i keep on getting the same failed to update error, and i don't know how to update manually. What do i do?

A search engine is your friend …

http://unity3d.com/webplayer/

i’ve installed that almost 4 times, but i figured out the answer. Apparently my Internet Download Manager, is automatically capturing a download file whilst i’m accessing World Science Day. I’ve turned it off, and it’s fixed. Thank you for your comment.