Format for comments in your code is wrong, correct format is:

<!--Comment-->

All the tags with ! in them appear to be comments and need to be fixed.

>here is the code where i have and error in "!Menu" adn other parts and i pste it from a book of microsoft
>
>

><Window x:Class="Browser"
>    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
>    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>    Title="My Own Wpf Browser" Height="480" Width="640" Name="Browser"
>    Icon="face02.ico" SizeToContent="WidthAndHeight"
>    WindowStartupLocation="CenterScreen"   >
>    
>   <Grid Name="grid1">
>    <DockPanel x:Uid="DockPanel_1">
>        < !Menu Bar>
>        <Menu x:Uid="Menu_1" Background="White" Name="_MainMenu" DockPanel.Dock="Top">
>            <! Navigate Menu>
>            <MenuItem x:Uid="NavigateMenu" Header="_Navigate" />
>                <! Help Menu>
>                <MenuItem x:Uid="HelpMenu" Header="_Help">
>                    <MenuItem x:Uid="AboutMenu" Header="_About" />
>                    </MenuItem>
>        </Menu>
>    </DockPanel>
>    </Grid>
>
></Window>
>