Photoshop troubleshooting

OK, here’s your chance, if you’ve ever had an annoying problem in Photoshop that you think would be good for my troubleshooting faq, email me at alanna @ angrypirate.com (remove the spaces). If you give me a question, I’ll try to give you an answer in a day or two.

This is my list so far:
When I try to use a tool on my image nothing happens.
Most of the menu items are grayed out.
How do I select the contents of my layer?
My toolbox and palettes have disappeared.
I still donâ??t see any palettes.
When I convert my image from RGB to CMYK, my colors change drastically.
I am getting an error message that says my scratch disk is full. What is this?
Why does my cursor display cross hairs instead of the appropriate tool icon?
I canâ??t open my image in Camera Raw.