1-4 is system board (motherboard) failure.  But first try a CMOS memory clear.  Power off and remove AC power cable from power supply.  Open case and locate the CR2032 coin cell battery on the motherboard.  Remove the battery, wait 5 minutes and install a NEW battery. If this doesn't help then the motherboard is likely toast.  
My optiplex runs through multiple number combinations, before settling on the 1-4 number combination on a solid green power button light for a good 2 seconds before I turn it off, because I’m scared of loud noises and I know dell computers make loud beeps when the motherboard fails. What is a possible solution?
Problem with my PC