Going to need that EXACT error message, not a version you summarized as best you can remember and full of odd abbreviations that could be misinterpreted.
sir, having a HP Compaq desktop DX2280, INTEL(R) PENTIUM PROCESSOR
My problem is when i start , the screen is displayed - The cmpt has been removed . the machine cover has been removed since last system startup. pl ensure that any system access was authourised
at the bottom of the screen is
F1 to cont, F10 BIOS setup so on