What exactly does "doesn't start" mean? That's a little vague, isn't it? It usually helps to give as many details as possible about what you've already tried. How are you trying to run it, and what response do you get, if any? If you haven't tried launching it from a console yet, do that and see if it gives you any output.
I generally get a "profile is in use" pop-up dialog whenever I have similar problems with unclean shutdowns. Usually in cases like this it means the browser just didn't have a chance to delete the "lock" file in your profile directory when it came down. If you find one there, simply remove it and try again.
BTW, there are also two command line options, -safe-mode and -ProfileManager, that you can often use when you have problems. The first will run the program with all extensions disabled, and the second launches the profile manager, where you can create and/or delete profiles. If nothing else works, you can always create a new profile to use.