I actually had the same thing happen yesterday. A client's website was rendering weird and the layout was broken. Turns out IE10 was in compatibility mode for their entire organization. I was able to force the browser to use standards mode by placing some code in my skin file. There needs to be a meta tag placed in the head, right at the beginning of the head.

<meta http-equiv="X-UA-Compatible" content="IE=edge" />

The placement is crucial, so this is the code I used in my skin

for vb skins

<script runat="server">

    Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreRender

        Dim meta As Literal = New Literal()

        meta.Text = "<meta http-equiv=""X-UA-Compatible"" content=""IE=Edge"" />"

        Me.Page.Header.Controls.AddAt(1, meta)    

End Sub

</script>