If that doesn't work, are you on a Mac? If so, please post hang or crash report to Pastebin.com, then put a link to it here.
That worked fine yesterday - however today it has decided on to work.
I'm using Windows 7. If you look in the task manager it looks like it is working (but it gets to 27456K and stops).
Windows 7 doesn't provide a lot of useful information, unfortunately. It might help us figure out where the problem is, though, if you were able to provide a step by step desscription of exactly what you are doing when it fails, and what you see (especially the exact text of any error messages) after each step. If it's running in task manager that means it may be waiting off screen somewhere for a response from you to a hidden dialog, or some module isn't loading properly.