Html – Does not show dynamic submenus of the Menu control in asp.net

I have designed a menu control in master page. But its dynamic sub menus are hide behind the images whice is in content page called home.aspx. It shows the submenus at development phase but not at hosting time. Here is my code for a menu. Is there any problem in my code. One more thing is that when I open the website in mozilla it shows every submenus not in any version of internet explorer.

Any suggesstion will be appreciated.

<asp:Menu ID="NavigationMenu" ItemWrap="false" StaticEnableDefaultPopOutImage = "false" Orientation="Horizontal" DisappearAfter="250" runat="server" DynamicHorizontalOffset="3" MaximumDynamicDisplayLevels="3" DynamicVerticalOffset="5" StaticDisplayLevels="1">
                                               
 <Items>   
                                                <asp:MenuItem Text="Home" Value="Home" NavigateUrl="~/Home.aspx"/>
                                                
<asp:MenuItem Text="Company Overview" Value="Company Overview" NavigateUrl="~/AboutUs.aspx">
                                                  
  <asp:MenuItem Text="About Us" Value="About Us" NavigateUrl="~/AboutUs.aspx" />
                                                    
<asp:MenuItem Text="Management" Value="Management" NavigateUrl="~/Management.aspx" />    
</asp:MenuItem>
 <asp:MenuItem Text="Testimonials" Value="Testimonials" NavigateUrl="~/Testimonials.aspx" />
                                                 <asp:MenuItem Text="Services" Value="Services" NavigateUrl="~/FrontOfficeService.aspx">

                                                    <asp:MenuItem Text="Front Office" Value="Front Office" NavigateUrl="~/FrontOfficeService.aspx">
                                                    <asp:MenuItem Text="Billing Office" Value="Billing Office" NavigateUrl="~/BillingOfficeService.aspx">
                                                    <asp:MenuItem Text="Paperless Office" Value="Paperless Office" NavigateUrl="~/PaperlessOfficeService.aspx">
                                                
</asp:MenuItem>
                                                <asp:MenuItem Text="Contact Us" Value="Contact Us" NavigateUrl="~/ContactUs.aspx">    
                                                </Items>
                                                
<StaticMenuItemStyle ItemSpacing="5px" HorizontalPadding="5px" ForeColor="White" VerticalPadding="2px" Font-Bold="true" />
                                                <DynamicMenuItemStyle HorizontalPadding="5px" ForeColor="White" BackColor="Navy" VerticalPadding="2px" />     
                                                <Dynamichoverstyle BackColor="LightBlue" Font-Bold="true" />
                                                <DynamicSelectedStyle BackColor="Green" ForeColor="Gray" />
                                                <StaticSelectedStyle BackColor="Green" ForeColor="Teal" />
                                                </asp:Menu>

Thanks in advance.