Help!

I'm about to cry

I downloaded a demo for a game. Made a folder on my desktop to install the game into it. I accidently chose to install the game into my desktop instead of the folder on the desktop. So I canceled the instalation so that I could install in the right directory. Then a message pops up saying something like "removing already installed files". I go back to my desktop and I almost fall off my chair. Before it was almost full with stuff, and now theres 5 or 6 icons. I lost over 5 GB of important things. I tried to restart...nothing. Then I went to my savior which saved me from many big troubles in the past, system restore. That restored a few folders, but there were no files in the folders!

Please someone tell me there is a way to undo this deadly blow! What can I do?!