Why do the desktop icons look like generic icons and not the usual picture icons?
The desktop database may have lost track of which icon pictures belong with which icons. Rebuild your desktop by doing the following. Press and hold the shift key, the option key and the apple key and restart your machine. When your machine restarts you will see a message that the computer is starting with extensions off. You will then get a message asking if you want to rebuild the desktop. You can release the keys and click o.k. Once the computer is finished booting, restart it once more. This time, do not hold any keys downs. Just let it boot up normally.