Also.. Who still uses dashboard?!
Why wouldn't you? I can convert anything, look up stocks, check my CPU temps and look up a phone number in a junk call database, all on one screen. I LOVE it. It's true that Apple hasn't given it much attention but this feature is not useless.
To the OP. Type these few lines, one by one, in Terminal
(don't type the first line if you wish to retain the widgets you installed):
Code:
rm -r ~/Library/Widgets/*
rm ~/Library/Preferences/com.apple.dashboard*
rm ~/Library/Preferences/widget-*
killall Dock
And voila! Your Dashboard is back to default.