Menus open different in different browsers

[Simon27c]

Take a look at this - http://s385506566.websitehome.co.uk/

If it is ran in either chrome or safari it acts as it should (the sub menus open below the nav bar)

but in IE and Firefox it is very different and a problem (the sub menus open Above! the nav bar)

Any Ideas?

[Simon27c]

Also any ideas on how the sub menus can be centred, it is probably obvious but jeez am i struggling.

Thanks

[Simon27c]

Bump.

[Simon27c]

another bump