Thanks Eric,
I did what suggested thread said.
I changed the folder name as it was told, and delete all the extensions for DW once.
Then I restarted the machine and DW.
But when I start up DW again, the folder "configuration" is somehow created again automatically. The result; still hasn't changed. Nothing on the panel... not sure if this is because of "configuration" folder though.
Is there anything else I can do to fix the problem?
Or should I just re-install the DW?