有關JavaScript及Flash Player(Youtube)

我前排重裝過部電腦,
唔知點解裝完之後我上去youtube個網睇野既時候,
佢打住:
Hello, you either have JavaScript turned off or an old version of Macromedia's Flash Player. Get the latest flash player.

不過我係有裝到flash player架,
我諗住試下再裝多一次flash player啦,
去到佢個網,佢按下載安裝,
load一陣之後......就話我已經安裝左flash player 9,
唔俾我再安裝....

咁請問我而家要點做先可以好似以前咁睇到youtube呢?
又會唔會係如上面所講,我個JavaScript熄左呢???
如果係的話,我要點樣先可以開返佢呢????
唔該晒你地^_^"