played with compizconfig settings now my desktop icons disapeared with no response: how to reset compiz to default settings

I'm a new user of ubuntu and i use ubuntu 11.04 , when i tried to make special effects on desktop using compizconfig settings and checking on desktop cube and rotate cube and some other options , some warning windows about plugin condlicts had appeared , so i made disable to some ones , then desktop became non responsive and the icons disappeared all , what can i do to regain the default settings, thanks