Any change if you restart machine? Does it launch at least once after computer restart?
I assume that you click on Edit button and nothing happens after that. If that's the case, you can try following - http://bit.ly/HUzzBR ... Let's see if you are able to delete preferences or not.
On the drive on which you have installed PSE,on my machine it is on C:
Go to c:\Program Files\Adobe\Photoshop Elements 9\Locales\<locale>\Plug-Ins\Import-Exportand you will find twain plug-in. Remove that plug-in from that location and copy it somewhere else.
Now launch PSE and check if it works.
Try resetting the PSE preferences by
1. Close Elements.
2. Launch the Photoshop Elements Welcome Screen and hold down ctrl + alt + shift as you click Edit.
3. Continue to hold the keys until you see a message box asking if you want to delete Photoshop Elements settings file; click Yes. Elements will open with default preferences.
- Disable any anti-virus software just to confirm if it is not blocking PSE Editor.
In case any network printer is attached try to launch without network or printer uninstall.
try and let me know your comments.