I have a compaq evo that beeps twice and flashes compaq screen very quickly in upper right hand corner it says f12 network boot or f10 system boot in lower left corner it has a blue block that says f1 boot I've tried all of these options fifty times as soon as I touch one of those keys the screen goes blank an machine locks up if I don't pick a key [very quickly] it just goes blank and locks up any suggestions ? Thanks tallgrassdave