are you using Internet Explorer?
If you are, then
go to My Computer -> Docs n Setting -> go to your profile folder -> Temp Internet Files folder
all the .jpegs, .gifs, .css, .swf everything from a website that you visited would be in that folder.
Just go to that folder, look for your .swf. You can sort by types.
The path may be wrong. i am at sch now, and donot have access to My Computer.
I am assuming you are using WinXP.