My windows XP computer doesn't work anymore. How can I fix it?

I put a flash drive in the computer (the flash drive had pictures on it that were TIFF files) and when I tried opening the file, it took forever, so i deiced to close the window. When the window closed, everything on my desktop was gone. The menu bar was gone and all the icons were gone. I waited for it to come back, and it didn't so I turned off the computer manually. When I turned it back on, a blue screen would pop up telling me to remove all hard drives from the computer, when i had already done that. I can't get the blue screen to go away. I need this computer because I have many documents and pictures on it. How can I fix this, and get my computer going again?