Catalyst Question , 9700 pro

ok , i change from catalyst to omega , and my double monitor display doesnt seem to be working, (when i tick the box and then press apply to enable my secondary monitor it flickers on then off and then on my primary monitor the ticked box becomes empty again (no tick) ), so i was wondering how i could change back from omega to catalyst again, because last time i slapped in the catalyst CD and it caused display corruption , articles, help pls