Hi
I'd be a sore user too, if my computer did that!
Sorry I couldn't resist.
Is it logging you in under your correct User Account Name?
The desktop data may be saved someplace under the username that you were logged into.
Look in C:\ Users\ Username\ Desktop and see if your stuff is there.
Try downloading and installing Agent Ransack and run a search for any of the missing files, looking on your whole C drive and see if it finds them. Find one you'll probably fine them all.
http://www.mythicsoft.com/page.aspx?type=agentransack&page=home
If you have a restore point try going back to an earlier date.
Personally I never let Windows install updates automatically.
I have it set to download them and notify me so I can install them when I'm looking at it.
I don't trust it alone at night.
I've had issues in the past when I got up and found my computer had shut down and wouldn't boot so now I just turn it off at night. All it's doing is sucking in dog hair if I leave it on anyway.
This also gets back to my fanatical "Never save anything important in only one location" message.
I take this to extremes but only a few months ago my computer got hit by lightning, my paranoia saved me.
All my stuff was safe on external hard drives.
Good luck I know how frustrating it is to have stuff disappear.
But it really sound like you are not logged in as the same user, so you are seeing a different desktop.
Mike