Desktop is missing
I have 10.6.8 My son recently downloaded a game off the internet. Things started running really slow and when we rebooted, my desktop is missing. There are no folders or icons on the screen and no shortcuts at the bottom. IPhoto comes up automatically, and if X out of it, I lose all the drop down menus at the top. If I go into the drop down menus for IPhoto I can access system preferences and a few other things, but I cannot access Finder or other applications. I can get into most programs through the recently used option, but have no idea how to get my desktop, icons and drop down menus back to normal. Any thoughts would be appreciated. Thanks!
iMac, Mac OS X (10.6.8)