Hp computer starts. goes to hp screen then restarts after about 15 seconds.... what can i do?

the computer starts and goes to a screen that sais esc to change boot order and f12 for setup or whatever.. then it restarts.. how can i fix?Hp computer starts. goes to hp screen then restarts after about 15 seconds.... what can i do?
try starting it in safe mode. f8 or something should be the hotkey.

and maybe its something in the start up folder

C:\Documents and Settings\Blank\Start Menu\Programs\Startup

check it

or run msconfig and go to the start up tab. and check that list for something that could cause it