You are allowed to delete your post for 5 minutes after it's posted.
Delete
You must have a user account and be signed to perform this action.
you can try to run an "upgrade" to fix it.
try this:
www.www.yoursite.com/tools/upgrade?force=1... orwww.www.yoursite.com/index.php/tools/upgrade?force=1...
This takes away the need for a confirmation and forced the upgraded to be completed, it might restore your dashboard