Real strange problem?

So I was trying to run aMSN a program i just downloaded and everything went slow and the fan ran crazy on and off. I tried to forcequit aMSN but there was this little log thing that didn't get quit. I tried to get rid of this log everyway I knew with no success. So i just decided shutting down all the applications then shutting down the computer itself was the only think I knew to do so I did it but when I logged back on my desktop dock all went to OG settings. I had random school work and folders on the desktop all deleted. But when I started inspecting again all of my applications are still there under the Application folder but all the logs, histories, and personal prefrences were deleted from them. The only extra files that were saved were the ones in their designated Movies, Music, Documents folders. It's like if the slate was wiped clean but their are stills bit and piecies left. and also from the beginning the computer acted like it was never started before sortve because I didn't have to go through the username password process but the beginner video that pops up when you first use the computer and applications giving preferences and tutrorials on how to use them all happened. What just happened with my macbook and I know it's real long run but is there anyway to recover the few missing files.

Sorry if someone could move this to Macbook Pro section. I'm pretty sure I put it under there.

I would go to their forums and see if you can get help there. What you have described is very messy. I've never heard of that happening.