followed by one long beep, pause, short beep, long beep, pause and so on.
What do you mean "and so on?" Does the beeping repeat? Is there more to it? Are you sure that is an accurate description of the sequence? This is important...
if you have no video something is probably not passing bios, you could try resetting your bios. (pop little lithium battery out, and put it back in.)I'll elaborate on this