Problems with main menu

Hi,

I like to know how to show all my menu tree when I put the mouse over the menu item.

For example:
1. Products
1.1 Product 1
1.1.1 Product 1 Specifications
1.2 Product 2
1.2.1 Product 2 Specifications

If i put the mouse over the "products" menu Item, the 1.1 and 1.2 should be showed.

My problems are that:
- If I am at the home page and I put the mouse over 1. , nothing is showed...
- If I do a click in 1. , the menu dissapears...

Any idea?

Thanks!