When you use Pagelayout control you use some ArcMAP MXD file as a template. You can "delete" (or make invisible) the border and "LAYERS" label via editing this MXD file in ArcMAP.
Thanks dshats for your help
I haven't used one ArcMap MXD file with my PageLayout Control, I only created directly objects (Text, Line) on the PageLayout for my program. Do I need use the MXD file ? (I haven't known about its uses).
This is the easy way to define the things as you wish. I am not sure, but i think there is always "default" MXD is loaded ("LAYER" label and border). Try it, i think it will help you to do what you want.
It looks like you have configured a MapFrame as your PageLayout. If so, look at the IMapFrame interface to control the border and other properties. The label in the middle disappers as soon as a layer is associated with the MapFrame. I do not think there is any other way to remove the center label.
You could also try casting to the IFrameElement interface, which controls a border on virtually all frame types. The IMapFrame inherits from that interface.