If your computer is failing to load properly and you are hearing beeps from the motherboard these are POST error codes. Pay close attention to the length and series of beeps as they will give you insight on what is causing the problem. Some of the most common series of beeps are listed below:

1 long, followed by 2 short beeps indicate either a Video adapter error indicating the card may not be properly seated in the slot. Try removing the card and reseating it. Also double check the cable connecting the monitor and any 6/8 pin power connectors are firmly connected.

1 long followed by 3 short beeps indicates no video card is recognized. Follow the steps above. If that doesn't work you will want to test another graphics card to ensure the PCIe slot is working. If you get the same error with 2 seperate cards it is likely either the PCIe slot or PSU are not functioning. You will want to swap out the PSU. If you get the same result chances are its the slot. If the problem dissapates the problem was with the PSU.

 Repeating (endless loop) indicates a memory problem. Take out all but 1 DIMM and see if you can pass POST. If you can you will want to check each stick individually to see if one of the modules has gone bad. If they all work in slot 1 (or 5 on some motherboards) then test the slots individually to see where the problem occurs.