Finder crash after downloading Dropbox

I downloaded Dropbox and the Finder has crashed by blinking with the "restore windows"-window. Then I created another administrator account and from here deleted Dropbox. Then restarted and logged in to my normal account. Now Finder wasn't blinking like before but there is nothing viewable on the Desktop and when I click on Finder in the Dock several times it comes up with a window for a splitsecond then closes the window again. Then I can press it several times again and it comes up for a splitsecond and then closes again. When hitting the command-option-esc, the icon blinks here. I've actually also tried the killall Finder in terminal, but even this doesn't work. WHATTODO???