Without proper system information and otehr details nobody can know what is going on.
Mine won't open either. I've updated in the past, but now all i get is a spinning wheel. OSX Mavericks.
I would suggest to try the the steps listed in this help doc. Removing the OPM.DB should resolve this.
For those on OSX Mavericks, here is a link to show you how to repair the disk permissions which will help too.
Let me know if you are still having issue